JAMB UTME - Biology - 2024

Awọn alaye Idahun

The food nutrient with the highest energy value is lipids, which include fats and oils.

The reason lipids have the highest energy value is due to their chemical structure. They contain long chains of carbon and hydrogen atoms, which can store a significant amount of energy. When these bonds are broken down in the body, they release energy.

In terms of energy measurement, lipids provide about 9 calories per gram, whereas proteins and carbohydrates each provide about 4 calories per gram. Minerals do not provide energy but are essential for other bodily functions.

Therefore, lipids are more energy-dense and offer more energy per gram compared to other nutrients. This is why they are considered the food nutrient with the highest energy value.

Awọn alaye Idahun

The endocrine gland located in the part labelled 'I' is the pituitary gland.

The pituitary gland is a small, pea-sized gland located at the base of the brain, just below the hypothalamus, which connects to it. It is often referred to as the "master gland" because it plays a crucial role in regulating a wide variety of bodily functions by secreting hormones that control other glands in the endocrine system, such as the thyroid, adrenal glands, and reproductive organs.

Key Points:

• The pituitary gland is located at the base of the brain, making it likely to be represented by a part labelled in the diagram near the bottom of the brain structure.
• It works closely with the hypothalamus to oversee many functions including growth, metabolism, and reproductive processes.

Awọn alaye Idahun

During prophase I, homologous chromosomes from each parent pair up and exchange genetic material, a process known as crossing over. This process creates new combinations of genes in the resulting gametes. When two gametes unite during fertilization, the offspring will have a unique combination of DNA.

Genetic recombination during fertilization takes place in the prophase I stage of meiosis ( part labelled III)

Awọn alaye Idahun

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.

Awọn alaye Idahun

Tuberculosis, often abbreviated as TB, is a disease that primarily affects the lungs, although it can spread to other parts of the body. The **causative agent** of tuberculosis is a specific type of **bacteria** known as Mycobacterium tuberculosis.

To understand this better, let's break it down:

• Definition of Bacteria: Bacteria are microscopic, single-celled organisms. They can be found everywhere and can be helpful or harmful to humans. In the case of tuberculosis, the bacteria are harmful.
• Mycobacterium tuberculosis: This bacterium is rod-shaped and has a thick, waxy coat, which makes it different from many other types of bacteria. This unique structure allows it to survive in harsh environments, including the human body.

When someone with active tuberculosis coughs, sneezes, or even speaks, the bacteria can be spread through the air and inhaled by others, leading to new infections. This is why tuberculosis is described as a **contagious** disease.

Understanding that tuberculosis is caused by **bacteria** is crucial for its treatment and prevention. Antibiotics, which are medicines that specifically target bacterial infections, are used to treat and control the spread of tuberculosis.

In summary, it's important to recognize that tuberculosis is caused by a specific type of bacteria called Mycobacterium tuberculosis, which explains why antibiotics can be effective in its treatment.

Awọn alaye Idahun

In humans and many other organisms, there are two types of cells: **somatic cells** and **gametes**. **Somatic cells** are typical body cells and are **diploid**, meaning they contain two sets of chromosomes—one set from each parent. **Gametes** are reproductive cells (sperm and egg) and are **haploid**, meaning they contain only one set of chromosomes.

In this context, if a **somatic cell** has **8 chromosomes**, it means it is carrying two complete sets of 4 chromosomes each. In order to form a **gamete**, this diploid number must be reduced to a **haploid number** through the process of **meiosis**.

Therefore, the **number of chromosomes** in a **gamete** would be **half** the number of chromosomes in a **somatic cell**. This is because gametes need to have just one set of chromosomes to ensure that when two gametes meet during fertilization, they create a diploid organism.

Thus, if the **somatic cell** has **8 chromosomes**, each **gamete** will have **4 chromosomes**.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

A fruit formed from one flower with many carpels is referred to as an aggregate fruit.

Let me break that down further for clarity: When a single flower contains multiple ovaries (carpels), each of these ovaries can develop into a small fruit. These small fruits collectively form what is known as an aggregate fruit. This means that although the fruit appears to be one single entity, it is actually made up of many small fruits that are clustered together. Each small fruit in the cluster originates from a single ovary of the flower.

An example of an aggregate fruit is a raspberry or a blackberry, where the clustered small fruits can easily be observed.

Awọn alaye Idahun

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.

Awọn alaye Idahun

The type of circulatory system found in arthropods and some molluscs is called an open circulatory system.

In an open circulatory system, the blood does not always travel inside blood vessels. Instead, the heart pumps the blood into open cavities or spaces in the body, and hence the organs are directly in contact with the blood. Unlike a closed system, where blood circulates only within blood vessels, the open system allows the blood to flow freely around tissues before being re-collected and circulated again. This kind of system is common in invertebrates like arthropods (insects, spiders) and some molluscs (like snails and clams).

This approach to circulation is generally less efficient than a closed circulatory system because there is less control over the direction and speed of the blood flow. However, it works well for the metabolic needs of these animals. They do not require the high energy needs of more complex organisms, so this system is well-suited to their lifestyles and environments.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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**.

Awọn alaye Idahun

The diagram provided is not visible since this is a text-based interface. However, I can help explain the parts of an insect as they typically relate to the given options: abdomen, head, maxillae, and thorax. Typically, insects have three main body parts: the head, the thorax, and the abdomen. The maxillae are a part of the mouthparts, usually located on the head. Here is a simple explanation of these parts:

Head: The head is the front part of the insect's body where the eyes, antennae, and mouthparts, such as the maxillae, are located. It is the center for sensory input and feeding.

Thorax: Located just behind the head, the thorax is the middle section of an insect's body. It is where the legs and wings (if present) are attached. It contains muscles that help in movement.

Abdomen: The abdomen is the rear part of an insect's body. It contains vital organs such as those for digestion, excretion, and reproduction. It is generally more flexible than the thorax.

Maxillae: The maxillae are a part of the insect's mouthparts and are found on the head. They assist in manipulating food.

Based on the given options, if Part III is a section of an insect's body segmented into three prominent parts, it usually corresponds to the thorax or abdomen. Without the diagram, a precise answer cannot be given, but based on typical labeling, Part III is often referring to the middle segment; hence, the thorax is a likely match.

Awọn alaye Idahun

Blood group AB is considered a universal recipient because individuals with this blood type can receive blood from all other blood groups, including A, B, AB, and O. This is possible due to the presence of both A and B antigens on the surface of their red blood cells and the absence of anti-A and anti-B antibodies in their plasma.

Here’s a simple breakdown:

• Blood group A has A antigens and can only receive A or O blood.
• Blood group B has B antigens and can only receive B or O blood.
• Blood group O has no A or B antigens and can only receive O blood.
• Blood group AB has both A and B antigens and lacks antibodies against either, allowing them to receive any blood type – A, B, AB, or O.

This makes AB blood group the universal recipient as they can accept A, B, AB, and O blood, without experiencing adverse reactions caused by antibody-antigen incompatibility.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

The major buffer in blood is the **bicarbonate buffer system**. The bicarbonate buffer system maintains the pH of the blood and is integral for physiological homeostasis. This system primarily involves **bicarbonate ions (HCO₃^-)** and works in conjunction with carbonic acid (H₂CO₃).

In the blood, the bicarbonate buffer system works by a reversible chemical reaction:

CO₂ + H₂O ⇋ H₂CO₃ ⇋ HCO₃^- + H⁺

Here’s how it functions:

• When the pH of the blood decreases (indicating high acidity), the excess hydrogen ions (H⁺) react with **bicarbonate ions** to form **carbonic acid**, which then converts to carbon dioxide and helps to raise the pH back to normal.
• Conversely, if the blood becomes too alkaline (higher pH), **carbonic acid** can release more hydrogen ions, lowering the pH back to the normal range.

This system is exceptionally effective at buffering rapid changes in pH. The respiratory and renal systems support the bicarbonate buffer system. The lungs regulate the concentration of CO₂, and the kidneys control the concentration of HCO₃^-.

While erythrocytes (red blood cells), leucocytes (white blood cells), and lymph are components of blood, they do not play a primary role in the buffering systems of blood. The bicarbonate buffer system is primarily a chemical buffer that functions independently of these cellular components.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

The oxygen that is transported to all parts of the body during blood circulation is primarily used for the release of energy from food. This process is also known as cellular respiration.

Here's how it works:

• Inside the cells, oxygen plays a crucial role in breaking down nutrients like glucose through a process called aerobic respiration.
• During aerobic respiration, glucose reacts with oxygen to produce carbon dioxide, water, and most importantly, energy in the form of adenosine triphosphate (ATP).
• ATP is the energy currency of the cell and is used to power various biological processes, enabling the cells and the body to function properly.

Thus, the presence of oxygen is vital for cells to convert the energy stored in food into a form that can be used for all activities, from metabolic processes to muscle contraction. In summary, the primary purpose of oxygen transportation during blood circulation is for the release of energy from food, which is essential for maintaining life and performing all physiological functions.

Awọn alaye Idahun

The term abiotic factors refers to the non-living components of an environment that can influence the growth and survival of organisms. In the given options, the factor that qualifies as an abiotic factor is rainfall. Abiotic factors are different from biotic factors, which involve living things such as predators, food availability, and diseases.

Explanation:

1. **Rainfall**: This is the only abiotic factor mentioned in the list. Rainfall provides water, which is essential for the survival of most organisms. It affects the availability of water resources, which are crucial for hydration of plants and animals, as well as for maintaining aquatic habitats. The amount, timing, and distribution of rainfall can influence the growth of plant populations, which in turn affects the availability of food and shelter for other organisms.

2. **Predator**: This is not an abiotic factor. Predators are living organisms that can directly influence the population of prey species by hunting and consuming them. This is a biotic interaction.

3. **Food Shortage**: Food availability is related to living organisms and is considered a biotic factor. Food shortage directly affects the survival and reproduction of organisms that depend on that food source.

4. **Disease**: This is again a biotic factor. Diseases are caused by pathogens, which are living organisms such as bacteria, viruses, or fungi, and they can spread among populations, reducing their size and growth.

In summary, rainfall is the abiotic factor from the choices given, and it plays a critical role in the environment by influencing water availability and ecosystem balance.

Awọn alaye Idahun

In considering the given options, the characteristic that is possessed by both living and non-living things is that they both have weight.

Here is the simple explanation:

• Both age and die: This characteristic applies exclusively to living things. Living organisms grow, age, and eventually die as part of their life cycle. Non-living things do not age or die.
• Both have life: By definition, only living things possess life. Non-living entities do not have life.
• Both have weight: This is the characteristic that applies to both living and non-living things. Every object that has mass is influenced by gravity, which gives it weight. Hence, both living organisms and non-living objects have weight.
• Both have no shape: This is incorrect. While gases may have no definite shape, many non-living things like rocks, tables, or buildings have specific shapes. Conversely, many living organisms, like animals and plants, also have definite shapes.

Therefore, the characteristic of having weight is shared by both living and non-living things.

Awọn alaye Idahun

Xerophytes are mostly found in arid land. Arid lands are environments that receive very low rainfall, typically classified as deserts or semi-deserts. These areas are characterized by extreme dryness and have conditions that make it difficult for most plants to survive.

Xerophytes are a type of plant specifically adapted to survive in these dry environments. They have special features that help them conserve water. These adaptations include thick, waxy leaves, reduced leaf sizes, deep root systems, and the ability to store water in their tissues. By being able to withstand long periods of drought, xerophytes thrive where other plants cannot.

In contrast, areas like the tropical rainforest and montane forest are characterized by high levels of rainfall and humidity, which support a diverse range of plant and animal life. Similarly, the Sudan savanna has more rainfall than arid lands and supports grasslands and woody plants. Therefore, the environment of arid land is significant to the existence of xerophytes.

Awọn alaye Idahun

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).

Awọn alaye Idahun

The pigment responsible for carrying oxygen in the blood is haemoglobin. Haemoglobin is a complex protein found in red blood cells. Its primary function is to transport oxygen from the lungs to the rest of the body and return carbon dioxide from the body to the lungs for exhalation. Each haemoglobin molecule can bind to four oxygen molecules, allowing it to carry and efficiently distribute a large amount of oxygen throughout the body.

Here's a simple explanation of how it works:

• Haemoglobin binds with oxygen in the lungs, forming oxyhaemoglobin, which gives blood its bright red color.
• This oxyhaemoglobin travels through the bloodstream to tissues and organs, where it releases the oxygen for cell respiration.
• As it releases oxygen, it picks up carbon dioxide, a waste product from cells, and becomes deoxygenated, giving it a darker color.
• The deoxygenated blood returns to the lungs, where carbon dioxide is released, and the cycle repeats.

It is essential to note that while oxyhaemoglobin is simply haemoglobin that has combined with oxygen, the fundamental oxygen-carrying pigment itself is still haemoglobin.

Awọn alaye Idahun

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.

Awọn alaye Idahun

Inbreeding is highly discouraged in humans primarily because it can greatly increase the risk of hereditary diseases. When close relatives, who may share similar genetic traits, have children together, there is a higher probability that both parents carry the same recessive genes. These recessive genes could cause genetic disorders if inherited in pairs. In an outbred population, these recessive genes are less likely to pair up, thereby reducing the risk of such disorders.

Hereditary diseases include conditions like cystic fibrosis, sickle cell anemia, and Tay-Sachs disease. These diseases can cause severe health problems and affect the quality of life of those born with them. The higher genetic similarity between parents who are closely related increases the chances of these diseases manifesting in their offspring.

In addition, inbreeding can also lead to the phenomenon known as "inbreeding depression," which can cause a reduction in fertility, survivability, and growth rates due to the accumulation of deleterious alleles. This can contribute to an increased death rate of newborns or result in other developmental concerns.

In summary, inbreeding increases the likelihood of harmful genetic conditions being expressed and can significantly impact the health and survival of the offspring, which is why it is strongly discouraged in human societies.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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**.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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.

Awọn alaye Idahun

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. 

Awọn alaye Idahun

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.

Awọn alaye Idahun

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

Awọn alaye Idahun

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.