JAMB UTME - Biology - 2023

A biome characterized by hot summer, warm winter and treeless vegetation is

Bayanin Amsa

The biome characterized by hot summers, warm winters, and treeless vegetation is called a **temperate desert**. In this type of biome, the climate is generally dry, receiving very little rainfall throughout the year. The absence of trees in temperate deserts is primarily due to the harsh climate and the scarcity of water. The hot summers and warm winters create an environment that is not conducive for tree growth. Instead, you will find various types of plants adapted to survive in arid conditions, such as shrubs, grasses, and cacti. Temperate deserts can be found in regions like the Mojave Desert in the United States, the Gobi Desert in Asia, and the Patagonian Desert in South America. Despite the lack of trees, these deserts support a diverse range of wildlife that has adapted to survive in these arid conditions. This includes animals like reptiles, insects, small mammals, and birds. In summary, a temperate desert is a biome characterized by hot summers, warm winters, and treeless vegetation due to the harsh climate and low precipitation.

Ecological succession refers to

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Ecological succession refers to the gradual and predictable change in a community over time. It is a process in which an ecosystem or community goes through a series of changes, from one stable state to another, in a continuous and sequential manner.

During ecological succession, new species gradually replace existing ones in a given area. This change can occur due to various factors, such as natural events like wildfires or human activities like deforestation. These disturbances create opportunities for new species to colonize the area and establish themselves.

The process of ecological succession can be divided into two main types: primary succession and secondary succession. Primary succession occurs in areas that are devoid of any life, such as bare rock or volcanic lava. Here, the process starts with the colonization of pioneer species, like lichens and mosses, which break down the rock and create soil. This allows other plants and organisms to gradually establish themselves.

On the other hand, secondary succession occurs in areas that have been previously occupied by a community, but have experienced some form of disturbance, such as a forest fire or a clearing. In this case, the process starts with the re-establishment of species that were present before the disturbance.

Overall, ecological succession is an essential process that allows communities to adapt and change over time. It plays a crucial role in maintaining the balance and biodiversity of ecosystems. By understanding ecological succession, we can better comprehend how different species interact and how ecosystems respond to environmental changes.

Which of the following is the most inclusive level of classification in the Linnaean system?

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The most inclusive level of classification in the Linnaean system is the kingdom

Which of the following is a characteristic feature of Kingdom Plantae?

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One characteristic feature of Kingdom Plantae is the ability to perform photosynthesis. Photosynthesis is the process by which plants use sunlight, carbon dioxide, and water to produce glucose (a sugar) and release oxygen as a byproduct. This process occurs within specialized organelles called chloroplasts, which are found in plant cells. Chloroplasts contain a pigment called chlorophyll that absorbs light energy from the sun and facilitates the conversion of carbon dioxide and water into glucose and oxygen. Through photosynthesis, plants are able to produce their own food and energy, making them autotrophs. Autotrophs are organisms that can synthesize organic compounds from inorganic substances. This ability allows plants to sustain themselves and support the growth and development of their tissues and structures. The presence of chloroplasts and the ability to perform photosynthesis are crucial characteristics that differentiate Kingdom Plantae from other kingdoms, such as Kingdom Animalia. Animals lack chloroplasts and are unable to produce their own food through photosynthesis. Instead, animals usually obtain their energy by consuming other organisms, making them heterotrophs. Therefore, the correct characteristic feature of Kingdom Plantae is the ability to perform photosynthesis.

Which of the following is a primary source of pollution in aquatic ecosystems?

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One primary source of pollution in aquatic ecosystems is **industrial discharge**. Industrial discharge refers to the release of waste materials and pollutants from industries into water bodies such as rivers, lakes, and oceans. These pollutants can include chemicals, heavy metals, oils, and other harmful substances. When not properly managed or treated, industrial discharge can have detrimental effects on aquatic ecosystems. These pollutants can contaminate the water, making it toxic and unsuitable for aquatic life. They can also disrupt the balance of nutrients and oxygen levels in the water, leading to the decline of certain species and the proliferation of others. Furthermore, industrial discharge can result in the accumulation of pollutants in the tissues of aquatic organisms, which can then enter the food chain. This can have cascading effects on the entire ecosystem, including bioaccumulation and biomagnification, where the concentration of pollutants increases as they move up the food chain, endangering higher-level predators and even humans who consume contaminated seafood. While the other options mentioned (soil erosion, air pollution, and deforestation) can indirectly contribute to water pollution, industrial discharge is a direct and significant source of pollution in aquatic ecosystems. Proper management, regulation, and treatment of industrial waste are necessary to minimize its harmful impact on the environment.

Which of the following represents an example of ecological management and conservation through a biological association?

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Ecological management and conservation through a biological association refers to a practice where a specific ecological system is protected and managed by using the interactions and relationships between different organisms within that system. Out of the given options, the **establishment of marine protected areas** represents an example of ecological management and conservation through a biological association. Marine protected areas are specific zones in the ocean where human activities, such as fishing or oil drilling, are restricted or prohibited. They are designed to conserve and protect marine biodiversity, ecosystems, and natural resources. Marine protected areas work by allowing ecosystems to function naturally, and they rely on the interactions between the different organisms within the marine environment. By restricting human activities, these areas provide essential habitats for marine species to reproduce, feed, and seek shelter. The establishment of marine protected areas promotes ecological balance and helps protect vulnerable and endangered species. It also allows for the recovery and regeneration of damaged marine ecosystems. In summary, the establishment of marine protected areas represents an example of ecological management and conservation through a biological association because it utilizes the natural interactions and relationships between organisms in the marine environment to preserve and protect the ecosystem for future generations.

Which of the following is a male reproductive organ in humans?

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The male reproductive organ in humans is the Testis.

The testis is responsible for producing sperm, which are the male reproductive cells. These sperms are needed for the process of fertilization, which occurs when a sperm cell fuses with an egg cell to form a new individual.

The testis also produces hormones, primarily testosterone. This hormone is responsible for the development and maintenance of male secondary sexual characteristics, such as facial hair, deepening of the voice, and muscle growth. The testis is located outside the body within a sac called the scrotum.

This is because sperm production occurs at a temperature slightly lower than the body temperature. The testis contains tiny coiled tubes called seminiferous tubules, where the sperm are produced. These sperm cells then mature and are stored in a structure called the epididymis until ejaculation.

In summary, the testis is the male reproductive organ responsible for producing sperm and testosterone, which are vital for reproduction and the development of male sexual characteristics.

Which of the following are components of the skeletal system in humans?

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The skeletal system in humans is composed of bones and joints. Bones and joints are the primary components of the human skeletal system

Which of the following is an example of conserving resources in an ecosystem?

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Implementing sustainable fishing practices is an example of conserving resources in an ecosystem.

When we practice sustainable fishing, we are taking steps to ensure that fish populations can replenish and continue to thrive in their natural habitats.

This involves using fishing methods that minimize harm to the ecosystem, such as using selective fishing gear to avoid catching non-target species and setting catch limits to prevent overfishing. Sustainable fishing also includes protecting important fish habitats, like coral reefs and seagrass beds, which serve as breeding and nursery grounds for many species.

By preserving these habitats, we allow fish populations to grow and maintain their natural balance within the ecosystem. Conserving resources in an ecosystem is important because it helps maintain biodiversity, ensures the long-term availability of valuable resources, and supports the overall health and stability of the ecosystem.

By practicing sustainable fishing, we are not only preserving fish populations, but also safeguarding the livelihoods of communities that depend on fishing for their food and income. In contrast, the other options listed do not contribute to resource conservation in an ecosystem.

The excessive use of chemical fertilizers in agriculture can lead to water pollution and harm the soil's natural fertility. Introducing invasive species can disrupt the balance of an ecosystem by outcompeting native species and causing harm to the environment. Cutting down trees for timber production can lead to deforestation and the loss of habitat for many plants and animals.

Overall, implementing sustainable fishing practices is a responsible and effective way to conserve resources in an ecosystem, ensuring the continued health and sustainability of both marine life and the human communities that rely on it.

Which gland is responsible for producing the hormone insulin?

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The gland responsible for producing the hormone insulin is the pancreas.

The pancreas is a gland located in your abdomen, behind your stomach. It has two main functions: producing digestive enzymes to help break down food and producing hormones, including insulin.

Insulin is a very important hormone that plays a crucial role in regulating blood sugar levels. When we eat, our body breaks down carbohydrates into glucose, which is a form of sugar that our cells use for energy. Insulin helps regulate how much glucose is absorbed by our cells from the bloodstream. When you eat a meal, your pancreas detects the increase in blood sugar levels and releases insulin into the bloodstream.

The insulin acts like a key, allowing glucose to enter the cells and be used as energy. This helps lower the amount of glucose in the bloodstream and keeps it within a healthy range.

In summary, the pancreas is responsible for producing the hormone insulin, which helps regulate blood sugar levels by allowing glucose to enter the cells.

Which of the following traits is not visible in a person with Down syndrome?

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A person with Down syndrome may exhibit certain visible traits due to the presence of an extra copy of chromosome 21. However, one of the traits that is not visible in a person with Down syndrome is high muscle tone.

Down syndrome is a genetic condition that occurs when there is an extra copy of chromosome 21. This extra genetic material can cause various physical and cognitive characteristics.

Some of the visible traits commonly associated with Down syndrome include a short neck, small stature, and slant eyes. These features can be present in individuals with Down syndrome, although the severity and extent can vary.

However, high muscle tone is not typically observed in people with Down syndrome. On the contrary, individuals with Down syndrome often have low muscle tone, or hypotonia. This means their muscles are usually less toned or firm than those of individuals without Down syndrome.

It is important to note that while these traits may be common in individuals with Down syndrome, each person is unique and will demonstrate a range of characteristics. It is always beneficial to approach individuals with Down syndrome with respect, understanding, and inclusiveness.

Which of the following statements best describes the role of competition in the process of adaptation?

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The statement that best describes the role of competition in the process of adaptation is: Competition leads to the selection of individuals with favorable traits for survival and reproduction.

Competition refers to the struggle among individuals for limited resources, such as food, territory, mates, or other necessities for survival. In a population with limited resources, not all individuals can have access to them.

This competition creates a selective pressure which drives the process of adaptation. Adaptation is the process by which individuals become better suited to their environment over time.

Through competition, individuals with advantageous traits, which may include physical characteristics or behaviors, have a higher chance of surviving and reproducing successfully. This is because these individuals are better able to acquire the limited resources compared to those who do not possess these traits.

For example, in a population of birds, competition for food may be fierce. Birds with longer beaks may have an advantage in reaching and eating certain types of food that are otherwise inaccessible to birds with shorter beaks.

Over time, the birds with longer beaks are more likely to survive and pass on their longer beak trait to future generations. Therefore, competition plays a crucial role in the process of adaptation by selecting individuals with favorable traits, enabling them to survive, reproduce, and pass on those traits to future generations.

Which of the following blood vessels carries oxygenated blood away from the heart?

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The blood vessel that carries oxygenated blood away from the heart is called an **artery**. Arteries are like highways that transport blood from the heart to different parts of the body. They have thick and elastic walls to handle the pressure exerted by the pumping heart. When blood leaves the heart, it is rich in oxygen and nutrients, which it carries to the body's tissues for them to function properly. Oxygen is crucial for various bodily functions, such as energy production. Therefore, it is important that the oxygenated blood reaches all parts of the body. Arteries have a bright red color because of the oxygen-rich blood they carry. As the blood travels through the arteries, it branches out into smaller vessels called arterioles, which further divide into tiny blood vessels known as capillaries. Capillaries are very thin and narrow, allowing them to reach almost every cell in the body. Once the oxygen from the blood is delivered to the body's tissues through the capillaries, the deoxygenated blood containing waste products, such as carbon dioxide, is collected by tiny veins called venules. Venules join together to form larger veins, which carry the deoxygenated blood back to the heart. To summarize, arteries carry oxygenated blood away from the heart to the body's tissues, while veins carry deoxygenated blood back to the heart. Arteries are like highways that deliver the necessary oxygen and nutrients to keep our bodies functioning properly.

Digestive enzymes are responsible for

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Digestive enzymes play a crucial role in our digestive system. They are responsible for breaking down the food we eat into smaller molecules so that our bodies can absorb the nutrients more easily. When we eat, our food enters the stomach and then moves into the small intestine. Here, the digestive enzymes are released and start breaking down the carbohydrates, proteins, and fats present in our food. These enzymes help break down complex molecules into simpler ones. For example, amylase is an enzyme that breaks down carbohydrates into smaller sugar molecules like glucose. Proteases break down proteins into amino acids, while lipases break down fats into fatty acids and glycerol. Once these molecules are broken down, they can be easily absorbed into the bloodstream through the lining of the small intestine. This is where the nutrients are taken up by our body cells and used for energy, growth, and repair. In addition to breaking down food, digestive enzymes also help in regulating the pH of the digestive tract. The stomach, for instance, has a highly acidic environment due to the presence of hydrochloric acid. Digestive enzymes help maintain the optimal pH level needed for their proper functioning. Lastly, digestive enzymes are also involved in transporting food through the digestive system. Peristalsis, which is the movement of food through the digestive tract, is facilitated by these enzymes. In conclusion, digestive enzymes are responsible for breaking down our food into smaller molecules, absorbing the nutrients into the bloodstream, regulating the pH of the digestive tract, and transporting food through the digestive system. They play a vital role in ensuring proper digestion and nutrient absorption in our bodies.

Metamorphosis is a biological process that involves

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Metamorphosis is a biological process that involves the change in form and structure during the life cycle of certain organisms. This process happens in various organisms, such as insects and amphibians, but not all organisms experience metamorphosis. During metamorphosis, an organism goes through distinct stages of development, transitioning from one form to another. The transformation usually involves changes in physical appearance, behavior, and sometimes even habitat. For example, in the case of insects like butterflies, the process of metamorphosis starts from an egg. The egg hatches into a larva, often known as a caterpillar. The caterpillar then undergoes a period of growth, eating and storing energy. Eventually, it enters a stage called pupa or chrysalis. Inside the pupa, the caterpillar undergoes immense changes, such as the reorganization of its body and the formation of wings. Finally, it emerges as an adult butterfly, capable of reproducing. This transformation is driven by hormonal changes within the organism that control the growth and development of specific body structures and systems. Metamorphosis allows the organism to adapt to different stages of life, with each stage serving a specific purpose. In summary, metamorphosis is a fascinating biological process that involves the change in form and structure during the life cycle of certain organisms. It is a crucial part of their development, allowing them to undergo significant transformations and adapt to different stages of life.

Which process in the nutrient cycle converts atmospheric nitrogen into a form that plants can utilize?

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The process in the nutrient cycle that converts atmospheric nitrogen into a form that plants can utilize is called nitrogen fixation.

Nitrogen gas makes up about 78% of the Earth's atmosphere, but plants cannot directly use this form of nitrogen for their growth and development. They need nitrogen in a different chemical form, like ammonia or nitrate, to be able to absorb it from the soil and use it to build important molecules such as proteins and DNA.

Nitrogen fixation is the process by which atmospheric nitrogen gas is converted into these usable forms of nitrogen. This process is mainly carried out by specialized bacteria, known as nitrogen-fixing bacteria, that are found in the soil or in the root nodules of certain plants, like legumes (e.g., peas, beans, and clover).

These nitrogen-fixing bacteria have a unique ability to convert atmospheric nitrogen gas into ammonia through a series of biochemical reactions.

This ammonia can then be further converted into other forms, such as nitrate or ammonium, which can be taken up by plants and used for their growth.

So, nitrogen fixation is a crucial step in the nutrient cycle as it makes atmospheric nitrogen available to plants, which in turn, becomes a source of nitrogen for other organisms in the ecosystem.

Which of the following factors primarily affects the distribution of organisms in an ecosystem

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The factor that primarily affects the distribution of organisms in an ecosystem is **temperature**. Temperature plays a crucial role in determining where different organisms can survive and thrive. Organisms have specific temperature ranges called their "optimal temperature range", within which they can function and grow most effectively. This range varies for different species. Some organisms, such as tropical plants and animals, thrive in hotter temperatures, while others, like polar bears and Arctic plants, are adapted to colder temperatures. Temperature affects the distribution of organisms in several ways. First, it determines the availability of water. Warmer temperatures lead to evaporation and increased water vapor in the air, which can result in areas with high humidity. This higher humidity may support different types of organisms compared to areas with lower humidity. Second, temperature affects the metabolism and physiological processes of organisms. Higher temperatures generally speed up biological processes, while lower temperatures slow them down. As a result, organisms have specific temperature thresholds beyond which they struggle to survive. For example, if the temperature becomes too hot, certain plants may wilt or die, while cold-blooded animals like reptiles may become sluggish or unable to move. Third, temperature influences the growth and reproduction of organisms. Some plants require specific temperature conditions to flower and produce fruit, while animals may have specific temperature requirements for breeding and reproduction. Lastly, temperature also affects the availability of resources for organisms. Different temperatures may lead to variations in the abundance and distribution of food sources, as well as availability of shelter and other resources necessary for survival. In summary, temperature is the primary factor that affects the distribution of organisms in an ecosystem. It determines the availability of water, influences biological processes and metabolism, affects growth and reproduction, and impacts resource availability.

Behavioral adaptation for dealing with a hot climate could include

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Behavioral adaptation refers to the actions and behaviors that animals take to survive in their environment. When it comes to dealing with a hot climate, animals have developed various behavioral adaptations to help them cope with the high temperatures.

One example of a behavioral adaptation for dealing with a hot climate is hibernating during the hottest part of the day. Hibernation is a state of deep sleep or dormancy that animals enter to conserve energy and protect themselves from extreme temperatures. By hibernating during the hottest part of the day, animals can avoid exposure to the intense heat and reduce their risk of overheating.

Another behavioral adaptation is having large scales on the back of a lizard. These scales act as a protective layer, shielding the lizard from direct sunlight and reducing heat absorption. The large scales help to reflect sunlight away from the lizard's body, keeping it cooler in hot climates.

Contrary to what one might expect, feeding during the hottest part of the day can also be a behavioral adaptation to deal with a hot climate. While it may seem counterintuitive, by feeding during this time, animals can take advantage of the increased availability of food. Many insects and small animals are more active during the daytime to avoid predators that are less active in the heat. By feeding during the hottest part of the day, animals can also conserve energy and avoid the need to search for food in hotter conditions later on.

Lastly, having a small kidney to conserve water is another behavioral adaptation for dealing with a hot climate. In a hot environment, water becomes a scarce resource, so animals need to be efficient in conserving and utilizing it. Having a small kidney allows the animal to produce less urine and retain more water in its body, preventing dehydration.

In summary, behavioral adaptations for dealing with a hot climate include hibernating during the hottest part of the day, having large scales on the back of a lizard, feeding during the hottest part of the day, and having a small kidney to conserve water. These adaptations help animals minimize heat exposure, reduce water loss, and maximize energy efficiency in hot environments.

Which of the following is a difference between plant and animal cells?

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One of the main differences between plant and animal cells is that plant cells contain chloroplasts for photosynthesis, while animal cells do not. However, plant cells contain chloroplasts, which are organelles responsible for photosynthesis, enabling plants to convert sunlight into energy-rich molecules. Animal cells lack chloroplasts and obtain energy through other means, such as consuming organic matter.

Which of the following is an example of conserving resources in an ecosystem

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An example of conserving resources in an ecosystem is implementing sustainable fishing practices.

Sustainable fishing practices involve managing the fishing activities in a way that ensures the long-term health and productivity of the fish populations, as well as the surrounding ecosystem. By implementing sustainable fishing practices, fishermen take measures to prevent overfishing and reduce bycatch (unwanted or unintentionally caught species).

They also consider the reproductive cycle of the fish species and set limits on the number and size of fish that can be caught. This helps to maintain a healthy balance in the ecosystem by allowing fish populations to reproduce and regenerate.

It also avoids depleting the fish populations, which can have negative impacts on other organisms that depend on the fish for survival, as well as the livelihoods of fishermen. Additionally, sustainable fishing practices may involve using more selective fishing gear, such as traps or hooks, which can reduce damage to the surrounding habitat compared to destructive fishing methods.

Overall, sustainable fishing practices aim to conserve resources in an ecosystem by ensuring a sustainable and balanced relationship between human activities and the natural environment.

Germination is the process in which a seed

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Germination is the process in which a seed breaks dormancy and starts to grow into a mature plant. During germination, the seed absorbs water and nutrients from the soil, causing it to swell and soften. This allows the seed coat to crack open, revealing the young root known as the radicle. The radicle grows downward, anchoring the seedling into the ground and absorbing water and nutrients from the soil. As the seedling continues to grow, it develops leaves and stems, allowing it to eventually photosynthesize and produce its own food. In summary, germination is the starting point of a seed's growth, where it absorbs nutrients, breaks dormancy, and begins to develop into a mature plant capable of photosynthesis. Germination is a crucial stage in a plant's life cycle as it marks the beginning of its growth and the establishment of a new plant.

What is the tissue responsible for transporting water and minerals from the roots to the rest of the plant?

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The tissue responsible for transporting water and minerals from the roots to the rest of the plant is called the **xylem**. Xylem is a specialized plant tissue that is found in the stems and roots of plants. Its main function is to transport water, dissolved nutrients, and minerals from the roots, where they are absorbed, to the rest of the plant. The xylem is composed of several types of cells, including vessel elements and tracheids, which are long, tube-like structures. These cells are arranged end-to-end, forming a continuous pathway for water and minerals to flow through the plant. The movement of water and minerals in the xylem is driven by a process called transpiration. Transpiration occurs when water evaporates from the leaves of the plant through tiny pores called stomata. This creates a slight suction force, which pulls water up from the roots and through the xylem vessels. The xylem vessels are reinforced with a substance called lignin, which helps to provide support and prevent collapse. This allows the xylem to transport water and minerals against gravity, from the roots all the way up to the furthest leaves and branches of the plant. In summary, the xylem is the tissue responsible for transporting water and minerals from the roots to the rest of the plant. It uses specialized cells and the process of transpiration to create a continuous pathway for the movement of water and minerals throughout the plant.

Which of the following is an evolutionary trend commonly observed in organisms?

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Increased genetic diversity within populations is an evolutionary trend commonly observed in organisms. Evolution is the process by which species change and adapt over time.

One important factor in evolution is genetic diversity, which refers to the variety of genetic traits within a population. Genetic diversity is beneficial to a population because it increases its chances of survival.

When individuals within a population have different genetic traits, they may respond differently to changes in the environment. This variation allows some individuals to better adapt to changing conditions, ensuring the survival of the population as a whole.

Over time, species can develop new traits and characteristics through genetic mutations, recombination, and other mechanisms. These changes can lead to increased genetic diversity within a population.

Increased genetic diversity can also occur through immigration and gene flow, when individuals from other populations bring new genes into a population.

This can further enhance the genetic variety within a group. In summary, increased genetic diversity within populations is an evolutionary trend commonly observed in organisms.

It allows for better adaptation to changing environments and increased chances of survival for a population in the long run.

Which of the following statements best describes pollination in plants?

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Pollination is the process of transferring pollen from the anther to the stigma of a flower.
In simple terms, pollination is like the plant's way of reproduction. It involves the transfer of pollen, which contains the plant's male reproductive cells, from the anther (part of the flower where pollen is produced) to the stigma (part of the flower where pollen needs to land for fertilization).
This transfer can happen in different ways, depending on the plant species. It can be done by wind, insects, birds, or other animals. When pollen reaches the stigma, it can fertilize the female reproductive cells and lead to the formation of seeds and fruits.
To summarize, pollination is the essential step in plant reproduction where pollen is moved from the male part of the flower to the female part, allowing for the production of seeds.

Which of the following is NOT a part of the alimentary canal?

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The liver is NOT a part of the alimentary canal. The alimentary canal, also known as the digestive tract, is a long tube that starts from the mouth and ends at the anus. It is responsible for the process of digestion and absorption of nutrients from the food we eat.

The oesophagus is a muscular tube that connects the mouth to the stomach. It allows food to pass from the mouth to the stomach by a process called swallowing.

The small intestine is the longest part of the digestive tract, where most of the digestion and absorption of nutrients take place. It receives the partially digested food from the stomach and breaks it down further with the help of enzymes, before absorbing the nutrients into the bloodstream.

The large intestine is the final part of the digestive system. It is responsible for absorbing water and electrolytes from the remaining indigestible food matter, and forming solid waste (feces) that is expelled from the body. However, the liver is not a part of the alimentary canal. It is an important organ located in the upper right side of the abdomen.

The liver has numerous functions in the body, including production of bile, which helps in the digestion and absorption of fats. While the liver plays a crucial role in digestion, it is not a structural part of the alimentary canal itself.

In summary, the liver is NOT a part of the alimentary canal. The oesophagus, small intestine, and large intestine are all parts of the alimentary canal responsible for the digestion and absorption of nutrients.

In monohybrid inheritance, if an organism carries two different alleles for a particular gene, it is called:

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In monohybrid inheritance, if an organism carries two different alleles for a particular gene, it is called **heterozygous**. Let's break it down to understand why this is the correct answer. Genes are the units of heredity that determine traits in living organisms. Each gene exists in different forms called alleles. In monohybrid inheritance, we focus on the inheritance of a single gene from one generation to the next. When an organism has two copies of the same allele for a gene, it is called **homozygous** for that gene. Homozygous individuals can have two copies of the dominant allele (DD) or two copies of the recessive allele (dd). On the other hand, if an organism carries two different alleles for a gene, it is called **heterozygous**. Heterozygous individuals have one copy of the dominant allele and one copy of the recessive allele (Dd). In this case, the dominant allele often determines the visible trait, while the recessive allele is hidden or masked. To summarize, in monohybrid inheritance, if an organism carries two different alleles for a particular gene, it is called **heterozygous**.

Which of the following statements about viruses is true?

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Viruses require a host cell to replicate. Viruses are not living organisms on their own. They are tiny infectious agents that can only replicate and multiply inside the cells of other living organisms. In order to reproduce, viruses depend on a host cell. They infect the host cell and take control of its machinery, directing it to produce more viruses. This process of using the host cell's machinery for replication is known as the viral life cycle. Once the new viruses are produced, they can go on to infect other cells and continue the cycle of reproduction. Therefore, it is true that viruses need a host cell to replicate.

Which organs are part of the alimentary canal in the human digestive system?

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The organs that are part of the alimentary canal in the human digestive system are the **esophagus, stomach, pancreas, and small intestine**. **Esophagus**: It is a muscular tube that connects the mouth to the stomach. Its role is to transport food from the mouth to the stomach through a process called peristalsis, which is the contraction and relaxation of the muscles in the esophagus. **Stomach**: The stomach is a J-shaped organ located below your diaphragm in the upper-left side of your abdomen. It is an important part of the digestive system because it breaks down food into a liquid mixture called chyme. The stomach has strong muscles that churn and mix the food with digestive juices that contain acids and enzymes. **Pancreas**: The pancreas is a long, flat gland located behind the stomach. It has both endocrine and exocrine functions. In terms of digestion, the pancreas releases digestive enzymes into the small intestine to help break down carbohydrates, fats, and proteins. **Small Intestine**: The small intestine is a long, coiled tube that is the major site of digestion and absorption of nutrients. It is divided into three sections: the duodenum, jejunum, and ileum. The lining of the small intestine has tiny finger-like projections called villi, which increase its surface area for efficient absorption of nutrients into the bloodstream. It's important to note that while the salivary glands, tongue, pharynx, large intestine, appendix, and rectum are all important parts of the digestive system, they are not part of the alimentary canal. The salivary glands produce saliva, the tongue helps with chewing and swallowing, and the pharynx is the pathway for food and air. The large intestine, appendix, and rectum are mainly involved in the absorption of water, electrolytes, and the elimination of solid waste. To summarize, the organs that are part of the alimentary canal in the human digestive system are the **esophagus, stomach, pancreas, and small intestine**. These organs work together to break down food, absorb nutrients, and eliminate waste.

Which of the following best describes a natural habitat in ecology?

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A natural habitat in ecology refers to an **area where organisms naturally live and interact with their surroundings**. It is a place where various plants, animals, and other organisms coexist and depend on each other for survival. In a natural habitat, organisms have access to the necessary resources, such as food, water, and shelter, that enable them to thrive and reproduce. It is important to note that natural habitats can vary widely, ranging from forests and grasslands to deserts and oceans. They can be found in different parts of the world, each supporting a unique set of species that are adapted to their specific environment. The diversity and complexity of interactions within a natural habitat contribute to the overall resilience and balance of the ecosystem.

Which of the following is an example of physiological variation in organisms?

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Physiological variation refers to differences in physiological traits or functions among individuals within a species. Blood pressure is a physiological parameter that can vary among individuals based on factors such as genetics, health conditions, lifestyle, and environmental influences. Physiological variation encompasses variations in functions, processes, and internal characteristics of organisms, such as metabolic rates, hormone levels, enzyme activities, blood parameters, and other physiological traits.

Which of the following processes is involved in the reproduction of developing organisms?

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Reproduction in developing organisms involves the process of **fertilization**. Fertilization is the fusion of male and female gametes to form a zygote, which later develops into a new organism. During fertilization, a male gamete (sperm) and a female gamete (egg) combine to form a single cell called a zygote. This process usually occurs through sexual reproduction, where the male gametes are transferred to the female reproductive system, enabling the fusion of gametes. Fertilization is a crucial step in the reproductive cycle as it brings together the genetic material from both parents, contributing to the genetic diversity of the offspring. The zygote formed by fertilization undergoes cell division and differentiation, eventually developing into a new organism. Budding is a type of asexual reproduction where a new organism develops from an outgrowth or bud on the parent organism. This process involves the formation of a clone, as the offspring is genetically identical to the parent. Germination, on the other hand, is the process by which a seed develops into a new plant. It occurs in plant reproduction but is not directly involved in the reproduction of developing organisms. Pollination is an essential step in the sexual reproduction of flowering plants. It involves the transfer of pollen grains from the male part (anther) of a flower to the female part (stigma) of another flower, allowing fertilization to occur. While pollination is involved in the reproductive process of plants, it is not directly related to the reproduction of developing organisms. Therefore, out of the given options, the process directly involved in the reproduction of developing organisms is **fertilization**.

Which type of reproduction involves the fusion of gametes from two parents?

Bayanin Amsa

The type of reproduction that involves the fusion of gametes from two parents is sexual reproduction.

In this process, two parents contribute their genetic material to produce offspring that inherits traits from both parents. Sexual reproduction involves the fusion of two specialized cells called gametes.

Gametes are produced by the parents and they contain half of the genetic information of each parent. In most animals, the male parent produces small motile gametes called sperm, while the female parent produces larger non-motile gametes called eggs. During sexual reproduction, the sperm and egg unite in a process called fertilization. This fusion forms a new cell called a zygote.

The zygote then develops into an offspring with a unique combination of genetic traits inherited from both parents. The process of sexual reproduction introduces genetic diversity among offspring.

This genetic diversity is important for the survival and adaptation of species to changing environments. It allows for the combination and recombination of genetic traits, enhancing the chances of producing offspring with advantageous characteristics.

Overall, sexual reproduction is a complex and fascinating process that involves the fusion of gametes from two parents, leading to the creation of genetically diverse offspring.

Which of the following is a method of asexual reproduction in plants?

Bayanin Amsa

Vegetative propagation is a method of asexual reproduction in plants. It involves the production of new plants from vegetative parts of an existing plant, such as leaves, stems, or roots. In this process, specialized cells present in these vegetative parts undergo cell division and differentiation to form new plant structures.

These structures can develop into independent, full-grown plants that are genetically identical to the parent plant. Vegetative propagation occurs in various ways:

1. Stem cuttings: A portion of a stem (with leaf nodes) is cut from a parent plant and placed in a suitable medium, where it develops roots and grows into a new plant.

2. Root cuttings: Portions of a root are cut and planted, and they produce new shoots and roots, forming a new plant.

3. Leaf cuttings: Leaves are detached from a parent plant, and specific parts of the leaf develop into roots, stems, and eventually, new plants.

4. Suckers and runners: Some plants produce horizontal stems called runners or suckers that grow from the base of the parent plant. These stems develop roots and give rise to new plants.

This method of asexual reproduction is advantageous because it allows plants to produce offspring quickly without relying on pollination or fertilization. It also ensures that the offspring are genetically identical to the parent, maintaining desirable traits and characteristics.

In summary, vegetative propagation is a form of asexual reproduction in plants where new plants are produced from vegetative parts of an existing plant, such as stems, roots, or leaves. It helps plants multiply quickly and maintain genetic uniformity.

Which of the following soil types becomes less fertile due to the intense leaching caused by tropical rains?

Bayanin Amsa

Tropical rains can cause intense leaching, which is the process of nutrients being washed away from the soil. This leaching can have a significant impact on soil fertility. Out of the given options, the soil type that becomes less fertile due to intense leaching caused by tropical rains is laterite soil.

Laterite soil is formed in areas with high temperatures and heavy rainfall, such as tropical regions. It is usually found in regions with a tropical monsoon climate, such as parts of India, Southeast Asia, and parts of Africa.

Because of the intense rainfall in these regions, laterite soil experiences a high degree of leaching. The heavy rainwater carries away the essential nutrients from the soil, making it less fertile over time. These nutrients include vital elements like nitrogen, phosphorus, and potassium, which are crucial for plant growth. As a result of intense leaching, laterite soils can become impoverished and low in nutrients.

This can pose challenges for agriculture as plants need these nutrients to thrive. Therefore, it is important for farmers in such regions to practice appropriate soil management techniques, such as using organic fertilizers or crop rotation, to replenish and maintain the fertility of laterite soil.

Which of the following is evidence of evolution?

Bayanin Amsa

All of the options listed are evidence of evolution.

Similarities in embryonic development:

Embryos of different organisms often have similar structures and developmental stages. For example, in the early stages of development, a human embryo has gill slits, similar to those of fish embryos. These similarities suggest a common evolutionary ancestry, where different organisms share common developmental patterns.

Fossils of extinct organisms:

Fossils provide direct evidence of organisms that once lived on Earth but are now extinct. By studying the preserved remains of ancient organisms, scientists can piece together the history and evolution of life. Fossilized bones, teeth, shells, and imprints of plants and animals provide a record of past life forms and how they have changed over time.

Homologous structures in different species:

Homologous structures are similar structures found in different species that originated from a common ancestor. For example, the forelimbs of a human, a bat, and a whale all have the same basic bone structure, even though they are used for different purposes. This similarity suggests that these species share a common ancestor and have evolved over time to adapt to their specific environments.

These different lines of evidence collectively support the theory of evolution, which states that all living organisms are related and have changed over time through a process of descent with modification.

Which of the following is the correct classification of carbohydrates?

Bayanin Amsa

Carbohydrates are classified as macronutrients. Macronutrients are the nutrients that our bodies need in large amounts to provide energy and support various functions.

This classification is correct for carbohydrates because they are a primary source of energy for our bodies. Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. They are found in a variety of foods such as grains, fruits, vegetables, and dairy products.

Carbohydrates can be further categorized into three types: sugars, starches, and fibers. Sugars are simple carbohydrates that are quickly broken down by the body into glucose, which is used for immediate energy.

Examples of foods high in sugar include table sugar, honey, and fruits. Starches are complex carbohydrates made up of many sugar molecules linked together. They are found in foods like grains, potatoes, and legumes.

Starches take longer to digest and provide a more sustained release of energy compared to sugars. Fiber is also a complex carbohydrate that cannot be fully digested by the body. It passes through the digestive system largely intact and provides important health benefits such as promoting regular bowel movements and supporting gut health.

Fiber is found in foods like whole grains, fruits, vegetables, and legumes. In summary, carbohydrates are classified as macronutrients because they provide our bodies with energy.

They can be classified into sugars, starches, and fibers, each with its own role in our diet.

Which of the following statements best describes courtship behaviors in animals?

Bayanin Amsa

**Courtship behaviors involve displays and rituals performed by both males and females to attract a mate**. Courtship behaviors are not solely performed by males to establish dominance within a social group. They involve a combination of displays and rituals that are performed by both males and females to attract a mate. These behaviors can vary greatly across different animal species, but the main goal is to increase the chances of successful mating. During courtship, animals may engage in various actions such as displaying colorful feathers or plumage, singing or calling, performing intricate dances, releasing pheromones, or building nests. These behaviors are a way for individuals to communicate their attractiveness, health, and suitability as a potential mate. It is important to note that courtship behaviors are not exclusively performed by one gender. Both males and females participate in courtship, although the specific behaviors exhibited may differ between them. In some species, males may engage in competitive displays or fights to impress females, while females may choose their mates based on these displays. In summary, courtship behaviors involve displays and rituals performed by both males and females to attract a mate. They are not solely performed by one gender, and their purpose is to increase the chances of successful mating.

Which of the following is an example of an adaptation for survival in social insects?

Bayanin Amsa

Formation of complex caste systems is an example of an adaptation for survival in social insects. Social insects like ants, bees, and termites live in colonies and work together for the benefit of the entire colony.

Caste systems in social insects are the division of labor within the colony, where individuals are assigned specific roles and tasks based on their physical characteristics and abilities. These castes typically include workers, soldiers, and reproductive individuals such as queens and drones.

The formation of complex caste systems is an important adaptation that helps social insects survive and thrive. Each caste has specific functions and responsibilities. For example, workers are responsible for tasks like foraging for food, building and maintaining the nest, and caring for the young. Soldiers, on the other hand, are responsible for defending the colony against threats.

This division of labor allows social insects to efficiently allocate their resources and adapt to various environmental conditions. It increases their chances of survival and success as a colony.

By having specialized castes, social insects can provide different services simultaneously, allowing the colony to be more efficient and resilient.

Overall, the formation of complex caste systems is a remarkable adaptation in social insects that enables them to effectively carry out their survival tasks and thrive in their habitats.

Most fishes do not sink in water because of the presences of:
I. swim bladder
II. air bladder
III. air sacs
IV. air in spongy bones

Bayanin Amsa

Fishes have a swim bladder or air bladder which helps them to remain buoyant without sinking in water. They are present in the body cavity.

Which of the following options best describes adaptation for survival in organisms?

Bayanin Amsa

The option that best describes adaptation for survival in organisms is:

Adaptation is the inherited trait that increases an organism's chances of survival and reproduction in its environment.

Adaptation is a natural process that occurs over many generations. It involves the development of specific traits or characteristics that help an organism better survive and reproduce in its environment. These traits are passed down from parents to their offspring, ensuring that future generations are more suited to their environment.

These adaptations can take various forms, such as physical features, behaviors, or physiological processes, that enable an organism to better compete, find food, avoid predators, or reproduce. Examples of adaptations include camouflage, the ability to hibernate, or the presence of certain enzymes that allow an organism to consume specific types of food.

Adaptations are not acquired during an organism's lifetime, and they are not a result of purposeful changes made by the organism itself. Instead, adaptations are the result of natural selection, where organisms with advantageous traits have a greater chance of survival and reproduction. Through this process, over time, populations become better adapted to their specific environments.

In summary, adaptation is an inherited trait that increases an organism's chances of survival and reproduction in its environment, helping it thrive and pass on its advantageous traits to future generations.