JAMB UTME - Biology - 2024

The feeding relationship between ruminants and the bacteria in their digestive tract is

Answer Details

The feeding relationship between ruminants and the bacteria in their digestive tract is symbiotic. In this type of relationship, both the ruminants and the bacteria benefit from each other.

Here's how it works:

• Ruminants are animals such as cows, sheep, and goats. They consume a lot of plant materials, primarily grass, which is rich in cellulose. However, these animals cannot digest cellulose on their own.
• The bacteria living in their digestive tract, particularly in the rumen, help by breaking down cellulose into simpler compounds like fatty acids, which the ruminant can then absorb and use for energy.
• In return, these bacteria benefit by living in a warm and nutrient-rich environment where they can grow and multiply.

This mutual benefit showcases a symbiotic relationship, where both organisms support each other's survival and wellbeing.

The schlerenchyma tissues consist of

Answer Details

Schlerenchyma tissues are a type of plant tissue known for providing structural support. These tissues are composed of cells that are typically dead at maturity. The cell walls of schlerenchyma tissues are thickened with lignin, which makes them rigid and strong. These characteristics help in supporting the plant body and protecting the plant against external mechanical forces.

To clarify, let's consider the types of cells mentioned:

• Dead Cells: Schlerenchyma tissues consist predominantly of these, as the cells are dead at maturity and filled with lignin.
• Living Cells: These are not characteristic of schlerenchyma tissues. Living cells are more associated with other tissue types, like parenchyma.
• Tracheid Cells: These are specific types of conducting cells in the xylem part of vascular plants, which are different from schlerenchyma.
• Meristematic Cells: These are undifferentiated cells that are capable of division, found in growth regions of plants, unlike the hardened structure of schlerenchyma.

In summary, schlerenchyma tissues consist mainly of dead cells. Their primary role is structural support, making them distinct from tissues composed of living cells, tracheid cells, or meristematic cells.

The organisms that adopt swarming as an adaptation to overcome overcrowding are

Answer Details

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.

In glycolysis, glucose is broken down through series of reactions in the presence of enzyme and absence of oxygen to produce

Answer Details

Glycolysis is a biochemical process through which glucose, a six-carbon sugar, is broken down into two molecules of a three-carbon compound called **pyruvic acid** or **pyruvate**. This process occurs in the **absence of oxygen** and is also referred to as anaerobic respiration. During glycolysis, energy stored in glucose is released, and a net gain of **two molecules of ATP (adenosine triphosphate)** is produced, which serves as a direct energy source for cellular activities.

Here is a brief explanation of the main steps involved in glycolysis:

• Glucose is first phosphorylated and converted into different sugar intermediates through a series of enzyme-catalyzed reactions.
• These intermediates are then further processed to form **two molecules of pyruvic acid**.
• During these steps, energy in the form of ATP is produced. In total, four molecules of ATP are generated, but two of these are used up in the initial steps, leading to a **net gain of two ATP molecules.**
• The process also produces two molecules of NADH, another energy carrier, which could be utilized in other pathways if oxygen is available.

In summary, during glycolysis in the absence of oxygen, glucose is transformed into **pyruvic acid and a net gain of ATP molecules**, making the answer **pyruvic acid + ATP**.

Which of the following conditions causes aestivation in animals?

Answer Details

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.

The part of the inner ear that is responsible for hearing is

Answer Details

The part of the inner ear that is responsible for hearing is the cochlea.

The cochlea is a spiral-shaped, fluid-filled structure that looks a little like a snail shell. Its primary function is to convert sound waves from the air into electrical signals that can be interpreted by the brain as sound. Here's how it works:

• Sound waves enter the ear canal and cause vibrations in the ear drum.
• These vibrations are transmitted through the tiny bones in the middle ear and reach the cochlea in the inner ear.
• Inside the cochlea, the vibrations cause the fluid to move, which in turn moves tiny hair cells located on a structure known as the basilar membrane.
• The movement of these hair cells produces electrical signals.
• The electrical signals are then sent to the brain via the auditory nerve, where they are interpreted as sound.

Thus, the cochlea plays an essential role in the process of hearing by transforming sound vibrations into nerve impulses that the brain can understand.

The formation of cilia and flagella in living cells is carried out with the help of

Answer Details

The formation of cilia and flagella in living cells is primarily carried out with the help of centrioles.

In eukaryotic cells, cilia and flagella are long, hair-like structures that extend from the surface of the cell and are responsible for movement. They are made up of microtubules, which are protein structures. The base of a cilium or a flagellum is anchored to a cell by a structure called the basal body.

The basal body is very similar in structure to a centriole. Centrioles are cylinder-shaped organelles found in animal cells and are composed of microtubule triplets. When a cell is ready to produce cilia or flagella, the centrioles migrate to the surface of the cell and become basal bodies by aiding in the assembly and organization of these microtubules.

Therefore, the role of centrioles is crucial because they act as the organizing centers for the microtubule structures that comprise cilia and flagella. Without centrioles, a cell would not be able to form these important structures.

Bilateral symmetry,cylindrical bodies and double openings are characteristic features of

Answer Details

The features you mentioned, namely bilateral symmetry, cylindrical bodies, and double openings, are characteristic of nematodes.

Let's break it down further:

• Bilateral Symmetry: This means that if you draw a line down the middle of the organism, both halves will be mirror images of each other. Nematodes exhibit this kind of symmetry, which is quite common in more complex organisms as it allows for streamlined movement and efficient sensory processing.


• Cylindrical Bodies: Nematodes have long, tube-like bodies that look like a cylinder. This shape helps them move efficiently through their environment, which can be soil, water, or as parasites inside other organisms.


• Double Openings: Unlike some simpler organisms, nematodes have a complete digestive system with a mouth at one end and an anus at the other, allowing for more efficient digestion and nutrient absorption.

In contrast:

• Hydra: These primarily show radial symmetry and have a single opening for both intake and excretion.


• Protozoa and Protists: These are generally single-celled organisms and do not exhibit all three characteristics mentioned (bilateral symmetry, cylindrical bodies, and double openings). They have more varied body plans and structures.

Therefore, based on these descriptions, nematodes clearly align with the features of bilateral symmetry, cylindrical bodies, and double openings.

Use the diagram above to answer the questions that follow

The part labelled I is

Answer Details

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.

The depressed side of paramecium which is lined with cilia leads to a tube-like structure called

Answer Details

The depressed side of a paramecium that is lined with cilia leads to a tube-like structure called the buccal cavity, also known as the gullet.

Darwin's theory of evolution is based on the principle of 

Answer Details

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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Use the diagram above to answer the question that follows

The diagram above is

Answer Details

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.

The cone in the retina of eye is an example of

Answer Details

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.

The main excretory product of earthworm is

Answer Details

The main excretory product of an earthworm is urea, with some ammonia gas also being released.

Earthworm is an annelid whose major excretory products are: Urea ~ 50% , Ammonia ~ 20-40% , Creatinine and other nitrogenous compounds ~ 5%

Uric acid is the main excretory product of birds, reptiles, and some insects. 

The total number of ATP produced during glycolysis is

Answer Details

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.

One main feature of trees in the savanna habitat is the possession of

Answer Details

Trees in the savanna habitat have a typical characteristic that helps them survive in the unique conditions of this environment. One of the main features is the possession of thick, corky bark. Savannas often experience seasonal fires during the dry season. A thick, corky bark acts as a protective shield, insulating the tree from the intense heat and preventing damage to the vital inner tissues. This adaptation also helps minimize water loss by reducing evaporation, which is crucial in the savanna's typically dry conditions. Thus, the feature of thick, corky bark is essential for the survival and resilience of trees in the savanna.

The transmission of diseases through contamination of food is an economic importance of

Answer Details

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.

Answer Details

The main excretory products of plants during metabolism are carbon dioxide, excess water, and nitrogenous compounds.

Plants produce carbon dioxide as a metabolic waste product during respiration, while oxygen is a metabolic waste product from photosynthesis. Excretion of gaseous waste in plants takes place through stomatal pores on leaves. Oxygen released during photosynthesis is used for respiration while carbon dioxide released during respiration is used for photosynthesis.

Use the diagram above to answer the question that follows

The organ is responsible for

Answer Details

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.

The cells responsible for transmitting messages to the effectors are

Answer Details

The cells responsible for transmitting messages to the effectors are motor neurons. These neurons play a critical role in the nervous system by transmitting impulses from the central nervous system (such as the brain and spinal cord) towards the muscles and glands, which are collectively known as effectors.

Here's a simple breakdown of how this process works:

• Signal Initiation: The process begins with the central nervous system sending an electric signal.
• Transmission: The motor neurons receive the signals and carry them along their axons, which are long nerve fibers.
• Activation of Effectors: When the signal reaches the end of the motor neuron, it causes the release of neurotransmitters, which then stimulate the effectors. In response, muscles may contract, or glands may begin secretion.

Effectors are essential as they perform actions in response to neural signals, making motor neurons integral in generating coordinated movement and various physiological responses. In contrast, sensory neurons carry information from sensory receptors to the central nervous system, relay neurons (interneurons) facilitate communication within the central nervous system, and hair cells are specialized sensory receptors in the auditory and vestibular systems. Thus, the primary role of motor neurons is to convey signals to effectors to initiate a response or action.

The type of variation where there are no remarkable differences between the two extreme individuals is called

Answer Details

The type of variation where there are no remarkable differences between the two extreme individuals is called continuous variation.

In biology, variation refers to the differences among individuals within a population. When we refer to continuous variation, we're talking about traits that are measured on a scale and show a range of small differences between individuals. An example is human height or weight. In these cases, individuals do not fall into a finite or distinct number of categories, but rather display a smooth and gradual transition across a range.

This type of variation typically results from the combined effects of many genes (polygenic inheritance) and the influence of environmental factors. It presents as a continuous range of expression, forming a bell-shaped curve when graphed, rather than discrete categories. Because of this smooth transition without sharp differences, it's termed as continuous variation.

Which of the Nigeria states is Northern guinea savanna located?

Answer Details

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.

Which of these is a medium of transportation in plants?

Answer Details

In plants, the **medium of transportation** is primarily the **cell sap**. Cell sap is the liquid found inside the large central vacuole of plant cells, and it plays a key role in transporting nutrients, minerals, and waste products. The vacuole itself is an important component in maintaining cell turgor pressure, which helps keep the plant upright. The movement of cell sap helps distribute essential substances throughout the plant.

On the other hand, the other options do not serve as media for transportation in plants:

• The **nucleus** is the control center of the cell, containing genetic information and regulating cell functions.
• The **mitochondrion** is known as the powerhouse of the cell, producing energy through cellular respiration.
• The **ribosome** is involved in protein synthesis.

Therefore, for transportation within plants, the **cell sap** is the correct answer.

Answer Details

In a genetic cross, when we have a heterozygous red flower plant (Rr) and a white flowered plant (rr), we can use a Punnett square to determine the probability of each possible genotype of the offspring.

The parent genotypes are:

• Red flower plant: Rr
• White flower plant: rr

We can set up a Punnett square with the following alleles:

From the table, we can see the following possible outcomes for the offspring:

• Rr (heterozygous red) occurs in 2 out of 4 possible outcomes.
• rr (homozygous white) occurs in 2 out of 4 possible outcomes.

Therefore, the probability that the offspring will be Rr is 2 out of 4 (or 1/2).

The chemical and physical composition of soil is an example of

Answer Details

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.

The endocrine gland that is called the master gland is the

Answer Details

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.

Gaseous exchange takes place through the plasma membrane in

Answer Details

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.

Energy transfer in plants and animals are in the form of

Answer Details

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.

Cell division that involves the growth, development, repairs and replacement of worn out tissues is

Answer Details

The type of cell division that involves the growth, development, repair, and replacement of worn-out tissues is mitosis.

Mitosis is a process by which a single cell divides to produce two identical daughter cells. This process is crucial for several reasons:

• Growth: As an organism develops, it needs more cells to increase in size. Mitosis ensures that new cells are genetically identical to the original cell, allowing tissues to expand properly.
• Development: During an organism's lifecycle, cells must differentiate and divide to form different tissues and organs. Mitosis provides the mechanism for such divisions while maintaining genetic consistency across cells.
• Repair: If tissues are damaged, mitosis allows for the production of new cells to replace the damaged or dead ones, helping tissues to heal.
• Replacement of Worn-Out Cells: Cells naturally wear out over time. Mitosis allows for their continuous renewal, ensuring that tissues function properly and maintain their integrity.

The process involves several phases, including prophase, metaphase, anaphase, and telophase, each contributing to the accurate duplication and distribution of chromosomes to the daughter cells.

Hemophilia in humans is controlled by the 

Answer Details

Hemophilia in humans is controlled by a recessive gene found on the X chromosome. This means that the gene responsible for hemophilia is not dominant and it is located on one of the sex chromosomes, specifically the X chromosome.

Here is how it works:

• Humans have two types of sex chromosomes, X and Y. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).
• For hemophilia to occur, the recessive gene must be present on the X chromosome.
• In males: Since males have only one X chromosome, if they inherit the X chromosome with the hemophilia gene, they will have the condition because there is no second X chromosome to offset the effect.
• In females: Because females have two X chromosomes, they need two copies of the recessive gene (one from each parent) to exhibit the disease. If a female has only one copy of the hemophilia gene, she will be a carrier but typically won't show symptoms because the other X chromosome, which does not carry the hemophilia gene, compensates.

In conclusion, hemophilia is inherited as a sex-linked recessive trait. This explains why it is more commonly observed in males than in females.

Which of these pair of substances must be present for a seed to germinate in a laboratory set-up?

Answer Details

For a seed to germinate in a laboratory set-up, the key pair of substances required are heat and water.

Water is essential because it activates the enzymes that begin the germination process. When a seed absorbs water, it swells and breaks the seed coat. This process is known as imbibition, and it is the first step in germination. The absorbed water allows the enzymes to start breaking down stored food resources within the seed, providing the energy necessary for the growth of the embryonic plant.

Heat, on the other hand, is important because most seeds need to be within a certain temperature range to germinate effectively. Appropriate warmth can facilitate enzymatic activities and biochemical processes needed for growth. The required temperature varies between species, but generally, seeds need warmth to sprout successfully.

While microbes can contribute to soil fertility and the decomposition of organic material, they are not directly necessary for the germination process of seeds, nor is soil required in a controlled laboratory environment.

Similarly, while manure can provide nutrients in an outdoor setting, it is not a vital component in the controlled germination process in a lab. The focus in such controlled experiments is typically on the primary resources that directly aid in the seed's initial growth, namely water and suitable temperature from heat.

Comparative anatomy to study evidence for evolution depends on

Answer Details

**Comparative anatomy** involves studying the similarities and differences in the anatomy of different species. One of its main purposes in understanding **evolution** is to trace how organisms are related through common ancestry. When we look at the limbs of different animals, some specific features provide essential evidence for evolution.

A key feature often examined is the structure of the limbs of vertebrates, which have evolved to adapt to different environments and modes of living, but share a basic underlying structure. This shared structure is often referred to as the **pentadactyl limb** pattern. The term "pentadactyl" means **five-fingered** or having five digits.

In many vertebrates like humans, whales, bats, and so forth, this **five-fingered** limb structure can be observed, although it has evolved to perform different functions in each species. For example, a human hand, a bat's wing, and a whale's flipper all have the same basic arrangement of bones. This points to the fact that these species share a **common ancestor** and have evolved differently as they adapted to their environments.

Thus, comparative anatomy's focus on the **five-fingered** pattern in limbs is crucial as it provides **evidence** of evolutionary relationships among diverse species, illustrating how they have evolved from a shared ancestry.

Pentadactyl forelimb of vertebrate function due to differences in environment is

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. 

The part of the flower that develops into seed is

Answer Details

In the process of flowering and reproduction in plants, the part of the flower that develops into a seed is the ovule. Let me explain this in a simple manner:

Flowers are the reproductive structures of flowering plants. They consist of various parts, each with a specific role in reproduction.

• The ovule is located within the ovary of the flower. During the process of fertilization, the ovule is fertilized by pollen, which contains the male gametes. Once fertilization occurs, the ovule develops into a seed. So, the ovule is the crucial part that, upon receiving pollen, transforms into a seed.
• The petal is not involved in the development of seeds. Petals are usually colorful and are meant to attract pollinators to the flower. They play no role in the development or transformation into seeds.
• The pedicel is the flower stalk that attaches the flower to the plant. It does not participate in seed formation.
• The style is a part of the female reproductive organ, but it serves only as a pathway for pollen tubes to reach the ovary where the ovule is situated. It does not develop into seeds.

Therefore, the correct answer is the ovule, as it is the part that transforms into a seed after fertilization.

The rhizoid of liverwort is

Answer Details

The rhizoid of liverwort is unicellular and unbranched.

Here's a simple explanation: Liverworts are a type of non-vascular plant that have structures called rhizoids. These rhizoids look like tiny hairs and they help the plant attach to surfaces like rocks or soil. Even though they help with attachment, they do not have the complexity of true roots.

In liverworts, these rhizoids are formed as single cells, which means they are unicellular. Think of them as being like a single long cell that looks like a hair. This single-celled structure is unbranched, meaning it doesn't split or divide into more parts or sections.

In summary, liverwort rhizoids are unicellular and unbranched, helping them secure the plant to various surfaces without forming complex root structures.

Which of the following plant is found in the ground layer of a tropical rainforest in Nigeria?

Answer Details

In a tropical rainforest, the forest layers are characterized by distinct types of vegetation. The **ground layer** hosts plants and organisms that typically thrive in low-light conditions due to the dense canopy above. Such layers often consist of mosses, ferns, and small plants that can grow with limited sunlight.

When considering the plants listed:

• Obeche and Mahogany are large trees that form part of the canopy or emergent layer, not the ground layer.
• Oil Palm is also a fairly large plant that grows in more open areas rather than the dense understorey of a rainforest.
• Liverwort is a type of small, non-vascular plant often found in the **ground layer**. It thrives in moist, shady environments, characteristic of the rainforest’s forest floor.

Thus, the answer is **liverwort**, as it appropriately matches the ecological niche of the **ground layer** in a tropical rainforest.

One of the following is an example of discontinuous variation

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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

Iron is a crucial nutrient for plants due to its involvement in several important biological processes. Let's break these down:

• Aids in the formation of chlorophyll and proteins: Without iron, plants cannot produce chlorophyll, the pigment that gives plants their green color and is essential for photosynthesis, the process through which plants convert sunlight into chemical energy. Additionally, iron is a component of some proteins and enzymes that facilitate various metabolic reactions within the plant.
• Helps in cell division: Iron plays a role in cell division and plant growth by being a part of enzymes that drive the synthesis of DNA. This is vital for the overall development and reproduction of plant cells.


• Protects the plants from pest attack: While iron is not primarily known for its role in pest protection, healthy plants, which benefit from sufficient iron, are generally more resilient to diseases and pests.
• Fastens fruits maturation: A well-functioning plant metabolism, aided by adequate iron levels, ensures that the plant's life cycle progresses timely, allowing fruits to mature at the right time.

In summary, iron is crucial because it is involved in the formation of chlorophyll, proteins, and DNA, all of which are essential for the growth, energy production, and reproduction of the plant. This, in turn, helps the plant grow healthy and resilient.

A trait that is always expressed during crossing of hereditary characteristics is

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When discussing the crossing of hereditary characteristics, a trait that is always expressed is known as a dominant trait. In genetics, traits are determined by genes, and each trait has two alleles, one from each parent. Alleles can either be dominant or recessive.

Dominant traits are those that are expressed in the organism's phenotype when at least one allele for the trait is dominant. This means that even if the organism has one dominant and one recessive allele for a trait, the dominant trait will take precedence and be observed in the individual.

Conversely, a recessive trait is only manifested in the phenotype if both alleles for that trait are recessive. Therefore, when a dominant allele is present, it will mask the expression of a recessive allele, resulting in the dominance of the trait in question.

For example, if a plant has one allele for tall height (dominant) and one for short height (recessive), the plant will appear tall because the tall allele is dominant.

Production of healthier offspring, viable seeds and formation of new varieties are good characteristics

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Cross-pollination is a type of pollination that produces healthier offspring, viable seeds, and new varieties.

Cross-pollination involves the transfer of pollen from the anther of one flower to the stigma of a different flower. In contrast, self-pollination is when pollen is transferred within a flower or between flowers on the same plant. Self-pollination is effective in a stable environment, but it can lead to weak offspring that are less adapted to the environment.