JAMB UTME - Biology - 2023

Which of the following plant tissues is responsible for transporting water and nutrients from the roots to the rest of the plant?

Answer Details

The plant tissue responsible for transporting water and nutrients from the roots to the rest of the plant is the **xylem**. Xylem is like the "plumbing system" of the plant. It is made up of long, hollow tubes called xylem vessels that run vertically from the roots to the leaves. These xylem vessels are stacked on top of each other, forming a continuous network throughout the plant. When water is absorbed by the roots, it travels through the xylem vessels upwards towards the rest of the plant. This process is called **transpiration**. Transpiration is the evaporation of water from the leaves, which creates a "pull" or suction force that helps to draw water up through the xylem. In addition to water, the xylem also transports nutrients, such as minerals and dissolved sugars, from the roots to the other parts of the plant. These nutrients are dissolved in water and are carried along with it as it moves through the xylem vessels. So, to summarize, the xylem is the plant tissue responsible for transporting water and nutrients from the roots to the rest of the plant. It acts like a "plumbing system" and uses transpiration to move water and dissolved nutrients upwards.

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

Answer Details

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

Answer Details

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 a difference between plant and animal cells?

Answer Details

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 characteristics is typical of the phylum Arthropoda?

Answer Details

The characteristic that is typical of the phylum Arthropoda is the presence of a segmented body.

Arthropods are a large and diverse group of animals that includes insects, spiders, crustaceans, and more. One of the key features that sets them apart is their segmented body. This means that their body is divided into repeating segments, or sections.

Each segment typically has its own pair of appendages, such as legs or wings, that serve various functions. Segmentation allows arthropods to have a high degree of flexibility and mobility. It also enables them to have specialized structures for specific purposes. For example, in insects, each segment of the abdomen may have its own set of muscles and structures related to breathing or reproduction.

The presence of a segmented body is a defining characteristic of the phylum Arthropoda and helps to distinguish them from other animal groups. In contrast to arthropods, animals with radial symmetry have body parts arranged around a central point, like the spokes of a wheel.

Closed circulatory system refers to the system in which blood flows through a series of vessels and is separate from the interstitial fluid. Endoskeletons made of bones are characteristic of vertebrates, like humans, while arthropods have exoskeletons made of chitin.

Which of the following statements about the heart is true?

Answer Details

The correct statement is: The heart is a muscular organ that contracts to circulate blood throughout the body.

The heart is a vital organ that keeps us alive by pumping blood continuously throughout our body. It is a muscular organ located in the chest, slightly tilted towards the left.

The main function of the heart is to circulate blood throughout the body, delivering oxygen and nutrients to all the organs and tissues. It does this by continuously contracting and relaxing, creating a pumping action.

The heart is made up of four chambers: two atria (singular: atrium) and two ventricles. The atria receive blood from the veins, while the ventricles pump the blood out of the heart. Deoxygenated blood, which has low oxygen levels and high carbon dioxide levels, enters the right atrium from the body through the superior and inferior vena cava.

The right atrium then contracts, pushing the blood into the right ventricle. From there, it is pumped to the lungs to get oxygenated. In the lungs, oxygen is added to the blood while carbon dioxide is removed. Oxygenated blood returns to the heart, specifically to the left atrium, through the pulmonary veins.

The left atrium contracts, pushing the blood into the left ventricle. The left ventricle, being the strongest chamber, pumps the oxygenated blood out of the heart and into the arteries that supply the rest of the body.

So, the heart does not produce red blood cells or receive blood from the kidneys. Its primary job is to pump oxygenated blood to the lungs for oxygenation and then pump the oxygen-rich blood to the rest of the body.

The term cell was given by

Answer Details

The term "cell" was given by Robert Hooke. He was an English scientist who lived in the 17th century. Hooke is famous for his book called "Micrographia," in which he described his observations under a microscope. In one of his observations, Hooke examined a thin slice of cork and noticed small compartments that reminded him of the empty rooms (cells) where monks lived in monasteries. He called these compartments "cells," and that's how the term came into existence. Although Hooke initially used the term to describe the structures he observed in cork, it was later found that cells are the fundamental units of life in all living organisms. Cells are the building blocks of life and are responsible for carrying out various functions necessary for an organism to survive and thrive. So, to summarize, the term "cell" was given by Robert Hooke when he observed small compartments in cork and named them after the rooms in monasteries. These cells are now known to be the basic units of life in all living organisms.

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

Answer Details

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 is a characteristic feature of Kingdom Plantae?

Answer Details

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.

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

Answer Details

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 statements is true regarding the urinary tubule in the excretory system?

Answer Details

The urinary tubule, a part of the nephron in the kidney, is indeed responsible for the production of urine. It does this by reabsorbing useful substances from the filtrate, such as glucose and ions, and secreting waste products into it. The modified filtrate, now called urine, is then passed on to the bladder for storage and eventual excretion.

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

Answer Details

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 the correct hierarchical organization of life from the smallest to the largest scale?

Answer Details

The correct hierarchical organization of life from the smallest to the largest scale is: **Cells, tissues, organs, organisms, populations, communities, ecosystems**. Let's break it down: - **Cells**: Cells are the basic units of life. They are the smallest structural and functional units that can carry out all the necessary functions of living organisms. - **Tissues**: Cells of similar types come together and perform specific functions, forming tissues. Tissues are groups of cells that work together to carry out a particular function in the body. - **Organs**: Organs are made up of different types of tissues that work together to perform a specific function. For example, the heart is an organ made up of cardiac muscle tissue, blood vessels, and connective tissue. - **Organisms**: Organisms are individual living beings consisting of multiple organ systems working together. They can be single-celled (like bacteria) or multicellular (like humans). - **Populations**: Populations refer to groups of individuals of the same species living in the same area and interacting with each other. For example, a population of deer living in a forest. - **Communities**: Communities encompass all the different populations of organisms that live and interact with each other within a specific area. For instance, a community could include populations of plants, animals, and microorganisms in a particular ecosystem. - **Ecosystems**: Ecosystems involve both the living organisms (communities) and the non-living components of a particular environment. This includes air, water, soil, and other physical factors. An ecosystem can be a forest, a lake, or even a small pond. So, in summary, the correct hierarchical organization of life from the smallest to the largest scale is: **Cells, tissues, organs, organisms, populations, communities, ecosystems**.

Which of the following statements best describes pollination in plants?

Answer Details

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 an evolutionary trend commonly observed in organisms?

Answer Details

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.

What is the primary source of variation in a population?

Answer Details

The primary source of variation in a population refers to the main factor that leads to differences or diversity among individuals within a species. In other words, it explains why individuals within the same species can look or behave differently from one another. One major source of variation is **mutation**. Mutations are random changes in the DNA sequence of an organism. They can occur naturally during DNA replication or as a result of exposure to certain environmental factors such as radiation or chemicals. Mutations introduce new genetic variations into a population, which can affect an individual's physical traits, behavior, or even their ability to survive and reproduce. Another significant source of variation is **gene flow**. Gene flow occurs when individuals or their genetic material migrate between different populations. This movement can bring in new genetic variants to a population or result in the loss of certain genetic traits. Gene flow helps to mix the gene pools of different populations and can contribute to the overall genetic diversity within a species. **Natural selection** is another important factor influencing variation. It is a process by which certain heritable traits become more or less common in a population over time, based on their influence on survival and reproduction. Individuals with advantageous traits that help them survive and reproduce are more likely to pass on these traits to their offspring. As a result, these traits become more prevalent in the population, while less advantageous traits may become less frequent or disappear altogether. Lastly, **genetic drift** is a source of variation that occurs by chance within small populations. It is influenced by random fluctuations in the frequency of certain genes within a population. Genetic drift can lead to the loss or fixation of certain genetic variants, particularly in small isolated populations or during population bottlenecks. This process can result in the reduction of genetic diversity in a population. In summary, the primary sources of variation in a population are **mutation**, **gene flow**, **natural selection**, and **genetic drift**. These factors work together, either independently or in combination, to shape the genetic diversity within a species.

Germination is the process in which a seed

Answer Details

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.

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

Answer Details

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.

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

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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.

Behavioral adaptation for dealing with a hot climate could include

Answer Details

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 organs is primarily responsible for excretion in humans?

Answer Details

The organ primarily responsible for excretion in humans is the **kidneys**. The kidneys are two bean-shaped organs located in the lower back on either side of the spine. These remarkable organs perform the vital function of filtering waste products and excess fluids from the blood, which are then eliminated from the body as urine. Here is a simplified explanation of how the kidneys carry out the excretion process: 1. **Filtration**: Every day, the kidneys filter around 200 liters of blood, separating waste materials such as urea, uric acid, and excess salts from the useful substances like water, glucose, and electrolytes. This filtration occurs in tiny structures within the kidneys called nephrons. 2. **Reabsorption**: After filtration, the kidneys reabsorb the useful substances, such as water and essential nutrients, back into the bloodstream. This allows the body to retain vital substances while eliminating waste. 3. **Secretion**: In addition to filtration and reabsorption, the kidneys also secrete certain waste products directly into the urine. These include substances like hydrogen ions and drugs. 4. **Concentration**: The kidneys also have the important task of maintaining the body's water balance. They regulate the concentration of urine based on the body's hydration needs. When we are dehydrated, the kidneys conserve water and produce concentrated urine. Conversely, when we are well-hydrated, the kidneys produce more dilute urine. The kidneys work closely with other organs involved in excretion, such as the liver and lungs, to maintain overall body balance. While the liver helps process and eliminate some waste products, and the lungs expel carbon dioxide, the kidneys are primarily responsible for the excretion of waste materials, particularly urea and other nitrogenous compounds. In conclusion, the **kidneys** play a crucial role in excretion by filtering waste products and excess fluids from the blood, while maintaining the body's water balance.

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

Answer Details

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.

Viviparity refers to the reproductive strategy in which

Answer Details

Viviparity refers to the reproductive strategy in which offspring develop and are nourished inside the female's body. This means that instead of laying eggs externally, like in other reproductive strategies, the female's body provides a protected environment for the embryo to develop and receive nutrients.

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

Answer Details

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 functions is performed by the skin to help maintain homeostasis in the human body?

Answer Details

The correct function performed by the skin to help maintain homeostasis in the human body is regulation of body temperature.

The skin plays a crucial role in maintaining a stable internal body temperature, regardless of the external environment. This process is known as thermoregulation. When our body gets too hot, the skin helps to cool it down, and when our body gets too cold, the skin helps to warm it up.

There are two main ways in which the skin helps regulate body temperature:

1. Sweat Glands: The skin contains sweat glands that produce sweat. When the body temperature rises, these sweat glands release sweat onto the surface of the skin. As the sweat evaporates, it takes away heat from the body, cooling it down.

2. Blood Vessels: The skin also has blood vessels near its surface. When the body temperature increases, these blood vessels expand, allowing more blood to flow through them. This increased blood flow helps to dissipate heat from the body. On the other hand, when the body temperature decreases, these blood vessels narrow, reducing the blood flow and conserving heat.

By regulating body temperature, the skin helps to maintain homeostasis, which is the body's ability to maintain a stable and balanced internal environment. This is essential for the proper functioning of various bodily processes and organs.

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

Answer Details

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.

The alternate form of a gene is

Answer Details

The alternate form of a gene is called an allele. An allele is a specific version or variant of a gene that codes for a particular trait or characteristic. Genes are sections of DNA that contain instructions for building and function of our bodies. They determine things like our eye color, hair texture, and the ability to taste certain flavors. Each gene can have different forms or variations, known as alleles. These alleles can be slightly different in their DNA sequence, resulting in different traits or characteristics being expressed. For example, the gene for eye color can have alleles for blue, brown, or green eyes. When a person inherits two different alleles of a gene, one from each parent, they are said to be heterozygous for that gene. In this case, one allele may be dominant, which means its trait will be expressed, while the other allele may be recessive, which means its trait will only be expressed if the dominant allele is not present. The way in which alleles interact with each other determines the inheritance patterns and the traits we observe. It is important to note that alleles can be dominant or recessive depending on the trait being considered. So, it is not accurate to say that alleles themselves are dominant or recessive, but rather how they interact with each other in the context of a specific gene.

Which of the following is an example of a microorganism in action as a disease vector?

Answer Details

An example of a microorganism in action as a disease vector is the mosquito transmitting malaria. Mosquitoes are tiny insects that can carry the malaria parasite from an infected person to a healthy person through their bites. Malaria is a disease caused by a microscopic parasite called Plasmodium. When a mosquito bites a person infected with malaria, it sucks up the Plasmodium parasites along with the person's blood. Inside the mosquito, the parasites go through a complex life cycle and multiply. When the mosquito bites another person, it injects saliva containing the malaria parasites into the healthy person's bloodstream. The parasites then travel to the person's liver and red blood cells, where they continue to multiply, causing the symptoms of malaria. This means that the mosquito acts as a vector, carrying and transmitting the disease-causing microorganism (Plasmodium) from one person to another. Mosquitoes are responsible for spreading malaria, which is a major health concern in many parts of the world, especially in tropical and subtropical regions. It's important to note that while fungi decomposing dead plant material, bacteria causing food poisoning, and algae producing oxygen through photosynthesis are all examples of microorganisms, they do not typically act as disease vectors like the mosquito in the case of malaria transmission.

Which of the following statements is true about the kingdom Fungi?

Answer Details

Fungi obtain nutrients by absorbing organic matter. This is a true statement about the kingdom Fungi. Unlike plants, which use photosynthesis to make their own food, fungi are heterotrophic organisms that get their energy by breaking down and absorbing organic materials around them. Fungi are not photosynthetic organisms. Photosynthesis is the process by which plants and some other organisms convert sunlight into energy. Fungi do not have chloroplasts or other structures needed for photosynthesis. Instead, they rely on obtaining nutrients from decaying organic matter or by forming symbiotic relationships with other organisms. Fungi can be both single-celled (yeasts) or multicellular (mushrooms, molds, etc.). Many fungi are multicellular organisms, composed of a network of thread-like structures called hyphae. These hyphae work together to form complex structures like mushrooms. However, there are also fungi that exist as single-celled organisms, such as yeast. Finally, fungi do not reproduce through the formation of seeds. Instead, they reproduce through spores. Spores are tiny structures that can be dispersed by wind, water, or other means. When conditions are favorable, these spores can germinate and develop into new fungal organisms. To summarize, the true statement about the kingdom Fungi is that they obtain nutrients by absorbing organic matter. They are not photosynthetic organisms, can be multicellular or single-celled, and reproduce through spores, not seeds.

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

Answer Details

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.

The theory of evolution can be defined as

Answer Details

The theory of evolution can be defined as the idea that species change over time through natural processes. It is the scientific explanation for the diversity of life on Earth.

According to this theory, all living organisms share a common ancestry and have gradually evolved into different species over millions of years.

Evolution is driven by natural processes such as genetic variation, mutation, natural selection, and genetic drift. These processes lead to changes in the inherited traits of organisms over generations.

Contrary to the belief that all species were created in their current form, the theory of evolution proposes that species evolve through a gradual process.

It is not a hypothesis that organisms strive to improve themselves over generations, as evolution does not have a goal or direction. Instead, it is a process that occurs due to factors such as environmental changes and the pressures of survival and reproduction.

Evolution does not occur through a series of sudden and dramatic changes, as stated in the fourth option. Rather, it is a slow and continuous process that happens over long periods of time. In summary, the theory of evolution is the concept that species change over time through natural processes.

It is supported by extensive scientific evidence from various fields of study, such as paleontology, genetics, and comparative anatomy.

Which of the following options correctly identifies excretory organs in animals?

Answer Details

The correct option that identifies excretory organs in animals is Lungs, kidneys, and skin.

Excretion is the process by which waste products are removed from an organism's body. Organisms produce waste as a result of their metabolic processes, and these waste products need to be eliminated from the body to maintain a healthy internal environment. Let's now examine each organ mentioned in the correct option:

1. Lungs: Lungs are the main respiratory organs in most animals. They play a crucial role in the process of respiration, which involves the exchange of gases between the body and the environment. During respiration, carbon dioxide, which is a waste product of cellular respiration, is eliminated through exhalation.

2. Kidneys: Kidneys are the primary excretory organs in animals. They filter the blood and regulate the composition of body fluids by removing waste products such as urea, excess water, and ions. The waste products filtered by the kidneys are then excreted as urine.

3. Skin: The skin, which is the largest organ in the body, also plays a role in excretion. It contains sweat glands that excrete sweat, a watery fluid that helps cool the body and removes certain waste products such as urea and salts.

In summary, the lungs eliminate carbon dioxide, the kidneys eliminate waste products through urine, and the skin excretes sweat. These three organs, lungs, kidneys, and skin, collectively facilitate the process of excretion in animals.

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

Answer Details

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.

Which of the following eye defects is caused by the inability of the eye to focus light on the retina?

Answer Details

The eye is a complex organ that allows us to see the world around us.

In order for us to have clear vision, light must be accurately focused onto the retina, which is located at the back of the eye.

Out of the options you provided, the eye defect that is caused by the inability of the eye to focus light on the retina is Myopia, also known as nearsightedness.

Myopia occurs when the eye is too long or the cornea (the clear front part of the eye) is too steep, causing light to be focused in front of the retina instead of directly on it.

This results in distant objects appearing blurry or out of focus, while nearby objects can still be seen clearly. To put it simply, in myopia, the eye is like a camera that is unable to properly focus the light onto the film.

Instead, the light falls short and focuses in front of the film, resulting in a blurry image. It's worth noting that myopia is a very common eye condition and can be corrected with the use of glasses, contact lenses, or even laser eye surgery.

These corrective measures help to redirect the incoming light so that it is properly focused onto the retina, allowing clear vision.

So, in summary, the eye defect caused by the inability to focus light on the retina is Myopia (nearsightedness).

The membrane around the vacuole is known as

Answer Details

The membrane around the vacuole is known as the **tonoplast**. The tonoplast is a special membrane that surrounds the vacuole, which is a large storage sac found in plant cells. It separates the contents of the vacuole from the rest of the cell. Think of the tonoplast like a protective bubble around the vacuole. It controls what goes in and out of the vacuole, just like a fence controls who can enter or exit a yard. The tonoplast is made up of proteins and lipids, which are like the building blocks that give it structure and function. One of the important functions of the tonoplast is to regulate the movement of water and other molecules in and out of the vacuole. It acts like a gatekeeper, allowing certain substances to enter or leave the vacuole while keeping others out. This helps the cell maintain its internal balance and prevents harmful substances from entering. Additionally, the tonoplast plays a role in maintaining the shape and stability of the vacuole. It helps the vacuole maintain its structure and prevents it from collapsing under pressure. So, to summarize, the membrane around the vacuole is called the tonoplast, and it serves as a protective barrier, regulates the movement of molecules, and helps maintain the shape of the vacuole.

Which of the following best describes physiological variation in biology?

Answer Details

Physiological variation refers to the differences in the physiological processes and functions of organisms. This means that organisms within a population may have unique ways of carrying out essential life processes, such as respiration, digestion, and circulation. These variations can be seen at the cellular, tissue, organ, and system levels. For example, different individuals may have variations in their metabolic rates, which affects how efficiently their bodies convert food into energy. Some individuals may have a higher metabolic rate, allowing them to burn calories faster and maintain a healthy weight more easily. On the other hand, some individuals may have a lower metabolic rate, making it harder for them to lose weight and requiring them to be more mindful of their calorie intake. Physiological variation also includes differences in the functioning of organs and systems. For instance, some individuals may have a stronger immune system, which helps them fight off infections more effectively. Others may have a genetically predisposed weakness in a particular organ or system, leading to potential health issues. It is important to note that physiological variation can be influenced by both genetic factors and environmental factors. Genetic factors contribute to the inherent differences in individuals' physiological processes, while environmental factors can modify or influence these processes. In summary, physiological variation encompasses the diverse ways in which organisms carry out their physiological processes and functions. These variations are seen at different levels, from cellular processes to organ systems, and can have significant impacts on an individual's health and overall well-being.

Which of the following is NOT a method of reproduction in animals?

Answer Details

Sporulation is NOT a method of reproduction in animals. Asexual reproduction is a method of reproduction where offspring are produced from a single parent without the involvement of gametes or fertilization.

This can occur through various mechanisms such as binary fission, budding, or regeneration. Budding is a form of asexual reproduction where a new individual develops from an outgrowth or bud on the parent organism. The new individual is genetically identical to the parent.

Sexual reproduction involves the fusion of gametes, which are specialized cells that carry genetic material, from two parent organisms. This process leads to the formation of genetically diverse offspring.

Sporulation is a form of reproduction commonly observed in some fungi, algae, and plants, but not in animals. Sporulation involves the production of spores that can develop into new individuals.

These spores can be dispersed through various means like wind, water, or animals, enabling them to reach new environments and colonize. In summary, while asexual reproduction, budding, and sexual reproduction are methods of reproduction in animals, sporulation is NOT a method of reproduction in animals.

Metamorphosis is a biological process that involves

Answer Details

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 of the following structures in the ear is responsible for transmitting sound vibrations to the auditory nerve?

Answer Details

The cochlea is a spiral-shaped structure in the inner ear that is filled with fluid and lined with cells with very fine hairs. These hairs move when the fluid in the cochlea moves, thereby converting sound vibrations into nerve signals that the brain can interpret. Therefore, the correct answer is 'Cochlea.' The eardrum and ossicles help to transmit sound vibrations to the cochlea, but it is the cochlea that transmits these vibrations as signals to the auditory nerve.

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

Answer Details

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.