JAMB UTME - Biology - 2024

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Gaseous exchange is a biological process through which different gases are transferred in opposite directions across a specialized respiratory surface. When it comes to simple organisms, this exchange can occur directly through the plasma membrane. The organism where gaseous exchange takes place through the plasma membrane is the paramecium.

Here is a simple explanation:

• Hydra: This is a simple aquatic organism; gaseous exchange can occur through its entire body surface because of its simple body structure.
• Paramecium: As a single-celled organism, paramecium relies on its plasma membrane for gaseous exchange. Oxygen from the surrounding water diffuses across the membrane into the cell, and carbon dioxide diffuses out. The plasma membrane is thin and semi-permeable, allowing this process to happen effectively.
• Flatworm: Flatworms have a larger surface area compared to their volume, and they also rely on diffusion through their body surface for gaseous exchange.
• Earthworm: This is a more complex organism. Earthworms have a moist skin through which gaseous exchange takes place. They possess a dense network of capillaries under the skin that facilitates this exchange.

In conclusion, paramecium utilizes its plasma membrane for gaseous exchange due to its single-celled structure, allowing direct diffusion of gases.

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Structures that are similar in form and origin but have been **modified** over time to function differently in various organisms are known as **homologous structures**. These structures indicate a common evolutionary ancestor. For example, the forelimbs of humans, bats, whales, and cats have the same basic bone structure but have adapted differently for tasks such as grabbing, flying, swimming, and walking. Each of these organisms developed modifications in their limb structure to suit their environment and lifestyle, which showcases the concept of homologous structures. Unlike **analogous structures** that have similar functions in different organisms but different evolutionary origins, homologous structures emphasize a common ancestry with different functional outcomes.

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To understand which plants exhibit hypogeal germination, we first need to comprehend what hypogeal germination is. In hypogeal germination, the cotyledons remain below the soil surface after the seed germinates. This occurs because the seedling's epicotyl (the part of the seedling above the cotyledons) elongates, pushing the shoot tip above the ground while the cotyledons stay buried, often serving their purpose as energy reserves.

Let's examine the given options:

• Castor Oil: This plant generally exhibits epigeal germination where the cotyledons come above the ground.
• Groundnut (Peanut): This plant shows hypogeal germination. Here, the cotyledons stay below the soil while the hypocotyl elongates.
• Maize (Corn): Maize undergoes hypogeal germination as its cotyledon remains underground. The seedling grows upward primarily due to elongation of the coleoptile, while the cotyledon stays below the soil.
• Orange: Orange plants are known for exhibiting epigeal germination, where the cotyledons rise above the ground.

From the options provided, both Groundnut and Maize exhibit hypogeal germination. While Groundnut's germination involves the cotyledons staying underground, Maize's germination follows a similar principle with its own adaptations.

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Insects have a specialized system for gas exchange, which does not rely on their skin like some other small organisms. Instead, they use a system known as the tracheal system. This system consists of a network of tiny tubes called tracheae.

The tracheae are the main structures that enable the exchange of gases in insects. These tubes extend throughout an insect's body and open to the outside through small openings on the insect's exoskeleton called spiracles.

When an insect breathes, air enters through the spiracles and travels through the tracheae, delivering oxygen directly to the body’s cells. At the same time, carbon dioxide, which is a waste product of respiration, exits the cells via the same tracheal system, leaving the body through the spiracles.

The tracheal system is highly efficient in distributing air directly to the tissues, bypassing the need for a circulatory system to transport gases throughout the body. As such, it provides a direct and effective way for insects to exchange gases necessary for respiration.

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Bryophytes are an intermediate group between higher algae and pteridophytes. Let's break this down to understand why.

Bryophytes include plants like mosses and liverworts. They are often referred to as the simplest form of land plants because they are non-vascular, meaning they do not have specialized tissues, like xylem and phloem, for water and nutrient transport. Instead, they rely on diffusion, which limits their size and requires them to live in moist environments.

On the other hand, pteridophytes are a group of plants that include ferns and are the next step up in complexity from bryophytes. They are important in this context because they mark the transition from non-vascular bryophytes to vascular plants (plants with vascular systems).

Why is this important? This transition is crucial because it represents the evolution of plants from simple, water-dependent organisms to more complex and diverse forms that can live in a wider range of environments, thanks to their vascular systems.

In summary, bryophytes serve as an evolutionary bridge between the simpler algae and the more complex pteridophytes due to their similarities and differences in structure and reproduction.

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One effective way of controlling Schistosomiasis is by destroying water snails and water weeds.

Schistosomiasis, also known as bilharzia, is a parasitic disease caused by trematode worms of the genus Schistosoma. The life cycle of these parasites heavily involves freshwater snails, which act as intermediate hosts. Here's how the life cycle works:

• The parasites reproduce inside humans and release eggs, some of which end up in freshwater bodies.
• The eggs hatch in the water to release larvae known as miracidia.
• These miracidia infect specific types of freshwater snails.
• Inside the snails, they develop into cercariae, which are another larval form of the parasite.
• These cercariae are released from snails back into the water, where they can penetrate human skin, continuing the cycle.

By destroying water snails and eliminating water weeds, which can provide habitat for these snails, you interrupt the lifecycle of the parasite. This can significantly reduce the risk of transmission to humans. It is crucial to control snail populations in freshwater bodies where human contact is common.

This method, along with other control measures such as providing access to safe water, improving sanitation, and educating communities about safe water practices, plays a crucial role in reducing schistosomiasis transmission. Importantly, to combat the disease effectively, a combination of approaches is usually necessary.

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Since I do not have access to the diagram mentioned, I will explain all the functions listed and how they relate to specific organs. You can then match the explanation with the organ shown in the diagram.

• Production of Heat: This function is typically related to muscles, primarily skeletal muscles. During physical activity, muscles contract and produce heat as a byproduct of metabolism. The liver is another organ involved in heat production through metabolic reactions.
• Osmoregulation: This function is primarily associated with the kidneys. The kidneys help maintain the balance of water and electrolytes in the body by filtering blood and forming urine, thus regulating the body's internal environment.
• Vasoconstriction: This process is often related to blood vessels, particularly the arterial system. It involves the narrowing of blood vessels, which increases blood pressure and reduces blood flow to certain areas. The nervous system, specifically the autonomic nervous system, plays a key role in regulating vasoconstriction.
• Production of Hormones: Many organs are involved in hormone production, including the hypothalamus, pituitary gland, thyroid gland, adrenal glands, pancreas, and reproductive organs. Each of these organs produces specific hormones that regulate various physiological functions in the body.

Identify the organ in the diagram and match it with the corresponding function explained above.

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The part labelled I in the diagram is the oviduct.

To understand why it is the oviduct, let's first understand what an oviduct is. The oviduct, also known as the fallopian tube, is a tube-like structure that connects the ovary to the uterus in female mammals. Its main function is to transport eggs from the ovaries towards the uterus. Fertilization of the egg by sperm typically occurs within the oviduct.

Now, let's look at the structure of the other options:

Placenta: The placenta is an organ that develops in the uterus during pregnancy. It provides oxygen and nutrients to the growing baby and removes waste products from the baby's blood.

Amnion: The amnion is a thin membrane that forms a protective sac filled with amniotic fluid around the developing embryo or fetus.

Uterus: The uterus is a muscular organ where a fertilized egg implants and grows into a fetus during pregnancy.

Based on the description and location given by the diagram, part I is most consistent with the oviduct, as it is likely representing the tube-like structure leading from the ovary to the uterus.

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The part labelled I in the given equation refers to sunlight.

Here is why:

The equation you've provided represents the chemical process of photosynthesis, which is how plants convert light energy into chemical energy stored in glucose (C₆H₁₂O₆). This process occurs in the chloroplasts of plant cells.

Sunlight is essential in this process because it provides the energy needed for photosynthesis to occur. This process begins when chlorophyll (labelled as III) within the chloroplasts absorbs sunlight, enabling the transformation of carbon dioxide (CO₂) and water (H₂O) into glucose and oxygen (O₂).

In summary, the part labelled I is sunlight because it is the energy source that drives the entire reaction of photosynthesis.

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When dealing with genetics, the genotypic ratio of offspring, particularly in the F1 generation, typically refers to the relative number of different genotypic combinations resulting from a genetic cross. To determine this ratio, it helps to construct a Punnett square, which is a grid that considers all possible combinations of parental genes.

In this specific scenario, although the diagram is not provided here, the genotypic ratio will depend on the types of alleles involved in the F1 generation. Most commonly in simple monohybrid crosses, if you're crossing two heterozygous organisms (e.g., Aa x Aa), the expected genotypic ratio is:

• 1 AA (homozygous dominant)
• 2 Aa (heterozygous)
• 1 aa (homozygous recessive)

Therefore, the genotypic ratio of the offspring produced in the F1 generation is 1:2:1.

The reasoning is straightforward: Each parent can contribute either one of two alleles. When combined in the F1 generation, they complete a set that falls into the three categories mentioned. Thus, when considering the options provided, the correct genotypic ratio for such a monohybrid cross is indeed 1:2:1.

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The flower is the reproductive organ of a plant. It is a plant organ, which is defined as a group of tissues that work together to perform a specific function. 

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The chemical and physical composition of soil is an example of an Edaphic factor.

Let's break this down:

Edaphic factors are the characteristics of the soil that influence the organisms living in it. These include the soil's chemical properties, such as its pH, nutrient content, and mineral composition, as well as its physical properties, like texture, structure, and moisture levels. They directly affect plant growth, as plants rely on soil for nutrients and support.

In contrast, the other factors mentioned are not directly related to soil composition:

• Climatic factors relate to weather conditions such as temperature, humidity, and rainfall.
• Topographic factors concern the landscape features like elevation and slope.
• While chemical factors might sound similar, they are more general and pertain to chemical aspects in various environments, not just soil.

Thus, when we talk about the chemical and physical composition of soil, we are specifically referring to its edaphic factors.

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The **answer** is insectivorous.

Here's why: In the plant kingdom, there are unique plants known as "carnivorous plants" that have the ability to capture and digest insects and other small animals. Despite obtaining nutrients from these creatures, they still perform photosynthesis, which means they are able to convert sunlight into energy just like any typical plant.

A carnivorous plant that specifically feeds on insects is termed insectivorous. These insectivorous plants have special adaptations such as sticky surfaces, pitcher-like traps, or rapid leaf movements that help them catch insects. Examples include the Venus flytrap and the pitcher plant.

So, while they do engage in capturing insects as a source of additional nutrients, they still depend on sunlight for their energy through the process of photosynthesis.

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A medium texture soil with high organic matter is best described as loamy soil. Here is why:

Loamy soil is a mix of three main soil types: sand, silt, and clay. This combination creates a soil that is rich in organic matter and nutrients, providing an excellent environment for plant growth.

Key Characteristics of Loamy Soil:

• It has a balanced texture, giving it good drainage and water retention capabilities, which are important for plant roots to access both air and water effectively.
• This soil type contains enough organic matter to support healthy plant life, as it facilitates nutrient absorption and microbial activity.
• Loamy soil is often referred to as the ideal gardening soil due to its ability to maintain structure and support plant health.

Understanding the benefits and characteristics of loamy soil can help in recognizing its importance in agriculture and gardening. Unlike clay or sandy soils, which might have issues with drainage or nutrient retention respectively, loamy soil offers a balance that is conducive for a wide variety of plants.

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The urinary tubules are part of the nephron, which is the basic functional unit of the kidney. Each nephron has several segments, including the proximal convoluted tubule, the loop of Henle, the distal convoluted tubule, and the collecting duct.

After the proximal convoluted tubule, the nephron forms a loop known as the loop of Henle. This loop dips down into the medulla of the kidney and is crucial for concentrating urine and maintaining water balance. The form that this loop takes is best described as a U-shaped loop. This shape is because the loop of Henle descends, makes a turn, and then ascends, forming a ‘U’ as it transitions eventually into the distal convoluted tubule.

Therefore, the correct description of the transition from the proximal convoluted tubule to the distal convoluted tubule, via the loop of Henle, is through a U-shaped loop.

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The **web-feet** of frogs and toads are primarily for **swimming**. Frogs and toads have webbed feet, which means their toes are connected by a thin membrane. This structure acts like a paddle, allowing them to push against water more effectively and move with greater ease and speed when they swim.

**Webbed feet** increase the surface area of their feet, providing more propulsion through the water, much like the way a duck's or other aquatic animal's webbed feet work. While they may also use their feet for other activities like **leaping** and **walking**, the primary adaptation and evolutionary advantage of having webbed feet is to enhance their ability to **swim** efficiently. Swimming is essential for frogs and toads because many of them live near water bodies and often have to escape predators, hunt for food, or move between land and water habitats.

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The process by which plants lose water to the atmosphere is referred to as transpiration. Let's break this down:

Transpiration is the process where water absorbed by plant roots is eventually released into the atmosphere as water vapor through the plant's leaves. This primarily occurs through small openings on the leaves known as stomata.

Here's how it happens:

• First, water is absorbed by the plant roots from the soil. This water moves up through the plant through structures known as xylem vessels.
• The water then reaches the leaves, where it helps in a vital process called photosynthesis. Excess water, however, evaporates into the atmosphere through the stomata.

Transpiration is crucial for plants because it not only helps them get rid of excess water but also plays a significant role in cooling the plant and enabling the upward movement of essential nutrients from the soil. It also contributes to the water cycle by adding moisture to the atmosphere.

In summary, transpiration is an essential process where plants lose water to the atmosphere, playing an important role in plant health and environmental equilibrium.

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The organelle that indicates the organism has plant characteristics is the chloroplast. Chloroplasts are essential because they contain chlorophyll, the green pigment crucial for photosynthesis. Photosynthesis is the process by which plants convert light energy from the sun into chemical energy stored in glucose, a type of sugar. This capability to conduct photosynthesis is a key characteristic that differentiates plants from animal cells.

Moreover, plant cells are generally characterized by having an additional cell structure which is the cell wall. The cell wall provides structural support and protection. However, in the context of identifying plant characteristics primarily through organelles, the chloroplast is the distinctive feature.

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To calculate the population density of a region, you need to divide the **total population** by the **area** they are living in. This will give you the number of people per unit area, typically per square kilometer in this case.

Given:

• Total population: 2,310,000 people
• Area: 2,310 square kilometers

The formula for population density is:

Population Density = Total Population / Area

By plugging in the given values:

Population Density = 2,310,000 / 2,310 = 1,000

This means there are **1,000 people per square kilometer** in this community. Therefore, the correct population density is **1,000**.

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The cone in the retina of the eye is an example of a cell. Let me explain this further in a simple and comprehensive way:

Our eyes have a part called the retina, which is like a screen at the back of the eye. It captures the images we see and sends them to the brain for processing. The retina contains special cells that help us detect light and color. These are primarily two types: rods and cones.

The cones are specialized cells in the retina responsible for allowing us to see in color. They function under bright light conditions and help us perceive different colors and details. There are three types of cones, each sensitive to: red, green, or blue light. Together, they allow us to see a full spectrum of colors.

Therefore, in the hierarchy of biological organization, a cone is considered a cell, as it is the smallest functional unit that contributes to vision.

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Darwin's theory of evolution is based on the principle of natural selection. This concept explains how species change over time in response to their environment.

Here's a simple way to understand it: In any given environment, there are more individuals born than can survive. These individuals vary slightly in their traits, such as color, size, speed, etc. Some of these variations might give an individual a slight edge in the environment, helping them to survive better or reproduce more than others. For example, a faster rabbit might escape predators more successfully than slower ones.

These advantageous traits are more likely to be passed down to the next generation. Over many generations, these beneficial traits become more common in the population. This process is known as natural selection because it "selects" the traits that best suit the environment. Consequently, the species slowly evolves and adapts to their surroundings.

The key point is that natural selection is a gradual process driven by the survival and reproduction of individuals with favorable traits in a specific environment. Unlike the other options, it doesn't rely on the use or disuse of organs, the inheritance of acquired characteristics during an individual's life, or sudden genetic changes known as mutations.

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Secondary succession is a process that occurs when an ecosystem that has already been colonized by living organisms is disturbed, but the soil and some of its organisms remain intact. This can happen after events such as forest fires, hurricanes, or human activities like farming. In contrast to primary succession, secondary succession does not start from scratch or a barren surface.

The characteristic of secondary succession is that it starts on an already colonized surface. This means that the area had life before but was disturbed, so the succession process is somewhat quicker since the soil contains seeds, nutrients, and microorganisms that speed up the recovery of the ecosystem. This contrasts with primary succession, which starts on bare and barren surfaces, like rocks or volcanic lava fields, where soil needs to form first.

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Glycolysis is the process through which one molecule of glucose is broken down into two molecules of pyruvate, and this process occurs in the cytoplasm of the cell. During glycolysis, two different phases are involved: the energy investment phase and the energy payoff phase. Let's break it down:

Energy Investment Phase: At the start of glycolysis, the cell uses 2 ATP molecules. This phase is necessary to modify the glucose molecule and prepare it for the subsequent reactions.

Energy Payoff Phase: As glycolysis continues, 4 ATP molecules are produced. These ATP molecules are formed when certain intermediates donate phosphate groups to ADP (adenosine diphosphate) to form ATP.

Hence, the net gain of ATP during the glycolytic process is calculated by subtracting the ATP used in the Energy Investment phase from those produced in the Energy Payoff phase.

The calculation is as follows:
ATP Produced = 4 molecules
ATP Used = 2 molecules
Net Gain = 4 - 2 = 2 molecules

Therefore, the total number of ATP produced during glycolysis, when considering the net gain, is 2 molecules of ATP.

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In the context of releasing oxygen to the atmosphere, only one of the processes you've listed does this: photosynthesis. Let me explain it in a simple way.

Photosynthesis is a process carried out by plants, some bacteria, and algae. These organisms use sunlight, carbon dioxide, and water to create their food, which is a form of sugar. As a byproduct, they release oxygen into the atmosphere. During this process, chlorophyll, the green pigment in plant cells, captures light energy, and helps convert it into chemical energy.

None of the other processes release oxygen:

- Respiration is a process in which living organisms, including plants and animals, take in oxygen and use it to convert glucose into energy, producing carbon dioxide and water as byproducts.

- Combustion involves burning substances, typically in the presence of oxygen, usually resulting in the production of carbon dioxide, water, and energy (heat and light). It does not release oxygen; rather, it consumes oxygen.

- Decomposition is the breakdown of dead organic matter by microorganisms. During this process, organic matter is converted back into carbon dioxide, methane, and other compounds, but it does not release oxygen.

So, the process that releases oxygen into the atmosphere is photosynthesis.

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The **pituitary gland** is known as the **"master gland"** of the endocrine system. Let us explore why this is important in a simple way.

The pituitary gland is a tiny, pea-sized organ located at the base of the brain, right behind the bridge of the nose. Despite its small size, it plays a crucial role in regulating vital body functions and general wellbeing.

Why is it called the master gland?

• Control over other glands: The pituitary gland produces and releases hormones that influence and regulate other endocrine glands such as the thyroid gland, adrenal glands, and reproductive glands (ovaries and testes). This is why it is known as the **master gland**.
• Stimulating hormones: It produces several hormones, known as **trophic hormones**, which travel through the bloodstream and tell other glands to produce their hormones. For instance, the pituitary releases thyroid-stimulating hormone (TSH) to regulate the thyroid gland.
• Growth and Development: The pituitary gland releases growth hormone which is critical for normal physical development in children and maintaining muscle and bone mass in adults.
• Well-being and Homeostasis: The hormones it secretes help control blood pressure, energy management, growth, reproduction, and aspects of your emotions.

In summary, the pituitary gland is termed the "master gland" because it has the ability to control many other glands within the endocrine system, playing a pivotal role in maintaining the body's environment or homeostasis.

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The transmission of diseases through contamination of food is an economic importance primarily related to cockroaches.

Cockroaches are considered pests that thrive in unsanitary environments. They are known to carry various pathogens, such as bacteria, viruses, and parasites, on their bodies and in their droppings. When they come into contact with food, they can contaminate it, leading to foodborne diseases.

This contamination can have several economic impacts:

• Health Care Costs: People who consume contaminated food may fall ill, leading to medical expenses for treatment and care.
• Workplace Productivity: Sick employees may need to take time off work, affecting productivity and economic output.
• Restaurant and Business Reputation: Establishments found to have unsanitary conditions due to cockroach infestations can face loss of customers, declining sales, and potential closure.
• Regulatory Fines: Businesses may incur fines or penalties from health and safety agencies if they fail to control cockroach infestations.

Therefore, managing and preventing cockroach infestations is crucial to safeguarding public health and protecting economic interests associated with food safety.

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The regulation of body temperature, thirst, and hunger is primarily managed by the hypothalamus. This is a small but crucial part of the brain located just below the thalamus. It plays a key role in maintaining the body's internal balance, known as homeostasis.

Here is a simple breakdown of its functions:

• Body Temperature: The hypothalamus acts like a thermostat, responding to changes in body temperature by triggering responses such as sweating to cool down or shivering to warm up.
• Thirst: When the body is low on water, the hypothalamus generates the sensation of thirst, prompting us to drink and restore proper hydration levels.
• Hunger: This part of the brain is sensitive to levels of glucose and other nutrients in the blood. It helps to trigger feelings of hunger when the body needs more energy, and signals fullness when enough food has been consumed.

The hypothalamus achieves these regulations by interacting with the endocrine system, releasing hormones that affect various bodily functions. So, if you are thinking of which area of the brain is in charge of these vital processes, the answer is indeed the hypothalamus.

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The diagram is that of the virus. Viruses are obligate parasites, meaning they can't produce their own energy or proteins. They enter the host cell and use the cell's machinery to make their own nucleic acids and proteins. Viruses also use the host cell's lipids and sugar chains to create their membranes and glycoproteins. This parasitic replication can severely damage the host cell, which can lead to disease or cell death. They usually enter your body through your mucous membranes. These include your eyes, nose, mouth, penis, vagina and anus.

Viruses are a unique type of organism that are not plants, animals, or bacteria. They are often classified in their own kingdom. However, for the sake of the question, since most of their attributes and metabolic activities are more of the bacteria, we'll go with option A - Monera

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The circulatory system is a network of blood vessels, the heart, and blood that moves throughout the body. The circulatory system's main function is to transport nutrients, oxygen, and hormones to the body's cells, and remove waste products. 

The reproductive system is a collection of organs in both males and females that work together to produce offspring, primarily consisting of the gonads (ovaries in females, testes in males) which create sex cells (eggs and sperm), and accessory organs that transport and nurture these cells to facilitate fertilization and potential pregnancy.

The nervous system is a complex network of nerves and nerve cells (neurons) that control bodily functions by sending signals between the brain and the rest of the body, allowing us to move, think, feel, and regulate internal processes; it consists of two main parts: the central nervous system (brain and spinal cord) and the peripheral nervous system

The urinary system helps the body maintain balance by removing waste products like urea, extra salt, and extra water. Urea is a waste product created when the body breaks down protein from foods like meat, poultry, and some vegetables. Its function is to remove waste from the body through urine bladder, urethra, kidneys and ureters.

Parts of the urinary system 

• Kidneys: Two bean-shaped organs located in the middle back, under the ribs. They filter blood to remove waste and extra water.
• Ureters: Two tubes that carry urine from the kidneys to the bladder.
• Bladder: A hollow organ in the pelvis that stores urine. When the bladder is full, it signals the body to urinate.
• Urethra: A small tube that carries urine from the bladder out of the body.

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In both plants and animals, **energy transfer** primarily occurs in the form of **Adenosine Triphosphate (ATP)**. To understand this, let's break it down simply:

1. **What is ATP?** ATP is a molecule that stores and carries energy within cells. Think of it as a small packet or currency of energy that is used to power various cellular processes. The energy is stored in the bonds between the phosphate groups, and when a bond is broken, energy is released to do work in the cell.

2. **How is ATP used in plants?** In plants, ATP is produced during the process of photosynthesis in the chloroplasts. Sunlight energy is captured and used to convert carbon dioxide and water into glucose and oxygen. The light energy is converted into chemical energy in the form of ATP and NADPH. Plants then use ATP to synthesize essential components like glucose, which further fuels various necessary activities of the plant.

3. **How is ATP used in animals?** In animals, ATP is primarily produced during cellular respiration in the mitochondria. Animals consume glucose, and through cellular respiration, they convert it into ATP by using oxygen. This ATP provides the energy needed for various functions such as muscle contraction, nerve impulse propagation, and biosynthetic reactions.

Other molecules like **DNA**, **RNA**, and **GTP** play different roles. DNA stores genetic information, RNA is involved in protein synthesis, and GTP is another energy molecule, but it is primarily used in specific signaling pathways and protein synthesis. ATP remains the main molecule for energy transfer in most cellular activities.

In summary, ATP is the **key energy carrier** in both plants and animals, facilitating essential life processes that require energy.

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Aestivation is a state of dormancy or reduced activity that animals enter to survive in hot, dry conditions or when food or water is scarce. 

Drought is a primary trigger for aestivation in animals, as it leads to water scarcity and increased temperatures.

While strong winds can be uncomfortable for animals, they don't typically trigger aestivation.

Rain is often associated with cooler temperatures and increased water availability.

Cold temperatures are more likely to trigger hibernation not aestivation.

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In blood transfusion, a patient with blood type **AB** is known as a **universal recipient**. This means they can receive red blood cells from any blood group. This is because:

• Blood type **AB** individuals have **both A and B antigens** on the surface of their red blood cells.
• They **do not produce any antibodies** against A or B antigens in their plasma, unlike other blood types.

Therefore, a person with blood type AB can safely receive red blood cells from **donors with A, B, AB, and O blood types**. This is because:

• **Group A donors**: Provide A antigens, which AB individuals accept.
• **Group B donors**: Provide B antigens, which AB individuals accept.
• **Group AB donors**: Provide both A and B antigens, which AB individuals accept.
• **Group O donors**: Provide no A or B antigens, making it compatible with all types.

Therefore, a patient with blood type AB can receive blood from donors with **group O, A, B, or AB**.

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The mouth parts adapted for piercing and sucking are found in the mosquito. Mosquitoes have specialized mouthparts known as a proboscis, which is designed to pierce the skin of their hosts and suck blood. This proboscis consists of a long, slender, and flexible tube that can penetrate the skin. Inside the proboscis are several delicate structures that help to hold the host's skin and locate blood vessels, allowing the mosquito to efficiently feed on blood.

In contrast, insects like the housefly have sponge-like mouthparts for lapping up liquids, the grasshopper has chewing mouthparts adapted for eating plants, and the cockroach also has chewing mouthparts suitable for a wide range of foods.

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One of the components of xylem tissue is the tracheid.

Let me explain this in simple terms:

The xylem is a type of plant tissue that is crucial for transporting water and nutrients from the roots to the rest of the plant. It plays a key role in plant hydration and nutrition.

Tracheids are long, tubular cells found within the xylem tissue. Their primary function is to help in the transport of water and minerals. Tracheids have thick walls and are dead at maturity, meaning they are hollow and create a continuous network for water flow. This structural arrangement also helps support the plant, providing rigidity and strength.

So, in summary, tracheids are an essential component of xylem tissue because they facilitate the movement of water and provide mechanical support.

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The **Northern Guinea Savanna** is an ecological zone in Nigeria characterized by a mixture of grasslands and scattered trees. This vegetation belt lies between the Sudan Savanna in the north and the Southern Guinea Savanna in the south. The vegetation in this region is adapted to longer wet seasons compared to the Sudan Savanna and shorter ones compared to the Southern Guinea Savanna.

Among the states listed, **Kwara State** is where the **Northern Guinea Savanna** is located. Kwara is positioned in the north-central part of Nigeria, which aligns with the geographical location of the Northern Guinea Savanna. It features the characteristic landscape of mixed grasslands and trees, supporting both agriculture and livestock rearing.

In contrast, **Borno and Kano** are located further north, closer to or within the Sudan Savanna zone, which is more arid. **Oyo state**, on the other hand, is located in the southwestern part of Nigeria and is part of the forested regions or the Southern Guinea Savanna, which receives more rainfall and supports more dense vegetation compared to the Northern Guinea Savanna.

Thus, the correct answer is **Kwara State** as it lies within the **Northern Guinea Savanna** ecological zone.

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The carbon cycle is a natural process through which carbon is exchanged between different components of the Earth, including the atmosphere, oceans, soil, and living organisms. The process in the carbon cycle related to your question is combustion.

Combustion is the process of burning organic material such as fossil fuels (coal, oil, and natural gas) or biomass (like wood). When these materials are burned, they react with oxygen to produce energy, releasing carbon dioxide (CO₂) and water vapor as by-products. This carbon dioxide is then released into the atmosphere, where it can be absorbed by plants through photosynthesis, thereby continuing the carbon cycle.

To clarify why the other processes are not part of the carbon cycle:

• Evaporation is the process where water from lakes, rivers, and oceans changes from a liquid to a gas or vapor. This is part of the water cycle, not the carbon cycle.


• Nitrification is a process in the nitrogen cycle, where ammonia is converted into nitrites and then nitrates, involving the transformation of nitrogen compounds. It does not involve carbon directly.


• Transpiration is the process through which water is absorbed by plant roots and then released as water vapor from plant leaves. This is also part of the water cycle.

In summary, combustion is the process in the list above that plays a direct role in the carbon cycle by releasing carbon dioxide into the atmosphere.

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Among the organisms listed, termites are well-known for adopting swarming as an adaptation to overcome overcrowding.

Here's why:

• Termites: In termite colonies, often when the colony becomes too large or overcrowded, a process known as "swarming" occurs. During swarming, winged reproductive termites, also called alates, leave the parent colony in large numbers to find a mate and establish new colonies. This swarming behavior helps reduce the population pressure on the original colony and allows for the spread and survival of the species.
• Tilapia: Fish like tilapia do not swarm as an adaptation to reduce overcrowding. While they might form schools, it is usually for protection, feeding, or migratory purposes rather than to resolve overcrowding.
• Rats: Rats don't adopt swarming behavior; instead, they disperse when populations become high, often seeking new habitats individually or in small groups.
• Agama Lizard: These lizards do not exhibit swarming behaviors. They are typically solitary or may live in loose groups but do not swarm as an adaptation for overcrowding.

Swarming in termites is a crucial natural strategy that allows them to efficiently manage their population and ensure the survival and expansion of their colonies.

Answer Details

Discontinuous variation refers to variations where the traits are distinct and categorical, meaning individuals can be grouped into distinct categories with no intermediate states. A good example of **discontinuous variation** from the options provided is **blood group**. This is because blood groups are distinct categories (e.g., A, B, AB, O) and individuals belong to one category without any intermediate states.

In contrast, other traits like **shape of the head**, **body complexion**, and **pointed nose** often show a range of variations that are continuous, meaning these traits can have many intermediate forms and cannot be easily categorized into discrete categories. Therefore, **blood group** is an **example of discontinuous variation** because it consists of clearly defined and non-overlapping categories.

Answer Details

A pentadactyl forelimb in vertebrates, meaning a forelimb with five digits, serves a variety of functions depending on the animal's environment, showcasing how a single basic structure can be adapted through evolution to suit different needs, like swimming, flying, running, or grasping, all while maintaining the underlying five-digit pattern as a result of shared ancestry. 

Physiological evidence is an evidence of evolution that deals with the functions of body parts among different species. For example, analogous structures are body parts of different species that have a similar function but can look different.

Moreover, physiological evidence focuses on the specific functional mechanisms and processes that underline the pentadactyl limb's operation while comparative anatomy addresses the evolutionary and anatomical origins of the pentadactyl plan. In other words, Anatomy is the study of the body's physical structure, while physiology is the study of how the body functions.

While both comparative anatomy and physiological evidence can support the concept of the pentadactyl forelimb in vertebrates, the key difference lies in the focus of study: comparative anatomy examines the structural similarities in bone arrangement across different species, whereas physiological evidence investigates how the limb functions and adapts to different behaviours in each species; essentially, comparative anatomy looks at the "blueprint" of the limb, while physiology examines how that structure is used in different contexts. 

Embryological evidence of the pentadactyl forelimb of vertebrates includes the regulation of gene expression during limb development. 

The fossil record of pentadactyl forelimbs shows that many vertebrates have a similar bone structure, even though their limbs look different on the outside. 

Answer Details

The marine habitat is divided into various zones, each with its own environmental conditions and challenges for the organisms living there. Among these zones, the intertidal zone is the one where organisms require significant adaptation for attachment. The intertidal zone is the area that is exposed to the air at low tide and submerged under water at high tide.

The main reasons organisms need adaptations for attachment in this zone are:

• Wave Action: The intertidal zone experiences strong waves and tidal currents that can easily dislodge organisms from the substrate. To survive, organisms like barnacles and mussels have developed strong attachments, like suction cups or byssal threads, that help them cling to rocks and other surfaces.
• Changing Environmental Conditions: As the tide rises and falls, organisms in the intertidal zone must endure both aquatic and terrestrial conditions. They need to remain attached to a stable surface to avoid being swept away by the tides.
• Preventing Desiccation: During low tide, when they are exposed to air, organisms must prevent drying out. Remaining attached to a secure surface allows them to find crevices or use their protective shells effectively.

Therefore, the intertidal zone specifically requires organisms to have adaptations that ensure they remain securely attached despite the dynamic and challenging conditions encountered daily.