JAMB UTME - Agricultural Science - 2024

In the nitrogen cycle , nitrite is oxidized to nitrate by

Answer Details

In the nitrogen cycle, the conversion of nitrite into nitrate is an important step. This process is known as nitrification. Nitrification is carried out by specific types of bacteria found in soil and water environments. The bacteria responsible for this transformation are primarily of the genus called Nitrobacter.

Nitrobacter bacteria play a crucial role by taking nitrite (NO₂^-), which is a less stable and less usable form of nitrogen for most plants, and converting it into nitrate (NO₃^-), which is a more stable and accessible form of nitrogen for plant uptake. This step is crucial because it makes nitrogen available in a form that can be easily absorbed by plants, thus supporting plant growth and development.

In summary, Nitrobacter are the bacteria responsible for oxidizing nitrite to nitrate in the nitrogen cycle.

Government laws and reforms are aimed at

Answer Details

Government laws and reforms in the agricultural sector are primarily aimed at increasing agricultural production. This is achieved through a variety of mechanisms, such as providing subsidies, implementing policies that support farmers, investing in agricultural research and technology, and ensuring access to resources like water and land. These efforts are designed to enhance the efficiency and productivity of agricultural activities. By increasing agricultural production, the government can ensure food security, reduce dependency on imports, and support the livelihood of farmers and related industries.

Which of the following will not lead to loss of nitrogen compound from the soil?

Answer Details

Let's go through the processes listed one by one to determine which does not lead to the loss of nitrogen compounds from the soil:

Burning: When organic matter, such as plant material, is burned, the nitrogen within that material is released into the atmosphere in the form of gases, such as nitrogen oxides and ammonia. This process results in the loss of nitrogen from the soil.

Crop Removal: When crops are harvested, the nitrogen contained in plant tissue is removed from the field and, thus, from the soil. This is because the plants absorb nitrogen from the soil as they grow, and harvesting takes that nitrogen away.

Lodging: Lodging involves the bending or breaking of crop plants near the ground, often due to environmental factors like wind or rain. This does not result in the loss of nitrogen from the soil because the nitrogen compounds remain in the plants and soil. Lodged plants continue to interact with the soil ecosystem, allowing nitrogen to be recycled back into the soil.

Leaching: Leaching occurs when water percolates through the soil and dissolves soluble nutrients, including nitrogen compounds like nitrates, which are then carried away deeper into the soil or into water bodies. This process leads to the loss of nitrogen from the root zone of the soil.

In conclusion, lodging does not lead to the loss of nitrogen compounds from the soil. It merely results in the physical displacement of plants but does not remove or transform the nitrogen compounds in a way that results in their loss from the soil ecosystem.

Which of the following statements is not correct about the land use act?

Answer Details

The Land Use Act is a policy that was enacted to manage and regulate land ownership and use. Here is an exploration of each statement:

• The government having control over unused land is a correct aspect of the Land Use Act, as it gives the government the power to allocate land based on its use and development priorities.
• The statement that land cannot be used for any purpose is incorrect. The Land Use Act actually allows land to be used for various purposes as long as it aligns with government policies and provides for economic and social development. Restrictions are only placed to ensure proper planning and sustainable use.
• Another objective of the Land Use Act is indeed the re-allocation of land for farming purposes among other uses to promote agricultural activities and boost food production.
• The Act is deliberately structured to prevent land fragmentation by consolidating land ownership to ensure optimal use and prevent the consequences of excessive subdivision.

Thus, the statement that land cannot be used for any purpose is the one that is not correct about the Land Use Act, as the Act actually facilitates multiple uses of land.

Which of the following does not fit into the agricultural use of land

Answer Details

The activity that does not fit into the agricultural use of land is mining. Here's why:

• Crop Production: This involves growing plants for food, fiber, and other uses. It requires preparing the land, planting seeds, and nurturing crops until harvest. This is a typical agricultural activity.
• Animal Production: This includes the raising of livestock, such as cattle, sheep, and poultry, for food, fiber, and other products. It is an integral part of agriculture.
• Forest Establishment: Although primarily not seen as agriculture, it can involve the planting and managing of forests for resources such as wood or to improve the environment, aligning it with sustainable land use practices in agriculture.
• Mining: This activity involves the extraction of minerals, ores, and resources from the Earth, which is fundamentally an industrial or geological activity, not related to agriculture. Mining does not typically contribute to the production of food or the management of land for biological growth.

New-born animals should be fed with colostrum because it

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New-born animals should be fed with colostrum primarily because it contains antibodies that protect them against diseases. Colostrum is the first milk produced by the mother shortly after giving birth. This special milk is rich in antibodies and nutrients essential for the new-born's health.

Antibodies are proteins that can fight infections and boost the immune system. By consuming colostrum, new-born animals receive immediate protection against common diseases and infections they might encounter in the first days of their life. This early protection is crucial because new-borns are particularly vulnerable to illnesses until their own immune systems are more developed.

While colostrum is also easily digested and is the first milk produced before birth, the primary reason it is so vital for new-borns is the presence of these protective antibodies.

Which of the following livestock endoparasite is a hermaphmdite?

Answer Details

To determine which of the mentioned livestock endoparasites is a hermaphrodite, it's important to understand what a hermaphrodite is. A hermaphrodite organism has both male and female reproductive organs, allowing it to reproduce without needing a mate of the opposite sex.

For each parasite:

• Trypanosome: These are protozoan parasites that cause diseases like sleeping sickness in humans and animals. They reproduce primarily through asexual means and are not hermaphroditic.


• Roundworm: Many roundworms have separate sexes, meaning they're not hermaphrodites. They usually reproduce sexually and require individuals of opposite sexes to mate.


• Liverfluke: Liverflukes, such as those from the genus Fasciola, are indeed hermaphrodites. They have both male and female reproductive organs and can self-fertilize or cross-fertilize with others. This adaptation helps ensure their survival and reproduction even if isolated.


• Tapeworm: Tapeworms are also hermaphrodites. Each segment of a tapeworm (called a proglottid) contains both male and female reproductive organs. They can self-fertilize, although cross-fertilization between proglottids of the same or different worms can occur.

Therefore, in the context of your question, both liverfluke and tapeworm are hermaphrodites. However, if choosing only one as a typical example of a hermaphroditic endoparasite, both can be valid responses, but tapeworm is often more prominently recognized.

The main aim of wildlife management is to

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The **main aim** of wildlife management is to prevent the extinction of species. Wildlife management involves the practices and strategies aimed at sustaining healthy animal populations and habitats. This field of study ensures that animal species do not disappear from our planet by addressing factors such as habitat degradation, overhunting, and the effects of climate change.

Conservation efforts focus on maintaining ecological balance and biodiversity, which is critical for the survival of numerous species. By protecting and managing wildlife and their habitats, we not only prevent species extinction but also sustain ecosystems that support all forms of life.

While concepts such as providing protein, controlling parasites, and generating income from wildlife might be related goals, they are not the primary focus. The ultimate objective of wildlife management is the conservation of biodiversity, ensuring that species continue to thrive for future generations.

Food shortage can be minimized by

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Food shortage is a significant issue that affects many parts of the world. One effective way to minimize food shortages is through the implementation of efficient pest control services. Pest control is critical because pests can destroy crops, leading to a substantial reduction in food supply. If pest populations are not managed, the damage to crops can be devastating, resulting in fewer yields. By using pest control services, farmers can protect their crops from insects, rodents, and other pests that threaten food production.

Here is a simple explanation of how efficient pest control can help minimize food shortages:

1. Protecting Crops: Efficient pest control services help in safeguarding plants from being consumed or damaged by pests. This means that more crops can be harvested and converted into food, helping to maintain an adequate food supply.

2. Improving Yield: When pest control measures are adopted, the quality and quantity of the harvest improve. Healthy crops mean more food can reach the market and consumers.

3. Promoting Sustainable Agriculture: By controlling pests efficiently, farmers can focus on sustainable farming practices rather than resorting to excessive chemical use. This approach not only protects the crops but also conserves the environment.

In conclusion, focusing on effective pest control is a key strategy in reducing food shortages. It plays a crucial role in protecting agricultural output, improving food quality, and ensuring that food supply remains stable and sufficient for the population.

The replacement of traditional farming methods with modern methods is a step in agricultural development

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The replacement of traditional farming methods with modern methods is indeed a step in agricultural development. Here's why:

Modern Methods refer to the use of advanced techniques, tools, and technologies in agriculture, such as tractors, genetically modified seeds, chemical fertilizers, and automated irrigation systems. These methods have several advantages:

• Increased Productivity: Modern methods lead to higher crop yields, which means more food can be produced with the same amount of land.
• Efficiency: The use of machinery and technology makes farming operations faster and less labor-intensive.
• Better Pest and Disease Management: Chemical fertilizers and pesticides help in protecting crops from pests and diseases, which otherwise would have reduced crop yields.
• Sustainability: Innovations like drip irrigation help in conserving water and ensuring that farming practices are environmentally sustainable.

By adopting these modern methods, farmers can not only maximize production but also ensure the sustainability and economic viability of their agricultural practices. This shift from traditional to modern methods represents a significant development in agriculture as it transforms the way farming is performed, leading to overall growth and efficiency in the agricultural sector.

Wastage of agricultural products during the harvesting period is mainly due to inadequate?

Answer Details

Wastage of agricultural products during the harvesting period is primarily due to inadequate storage and processing facilities. Let's break this down:

When crops are harvested, they need to be properly stored to maintain their quality and prevent spoilage. Without adequate storage facilities, farmers may not be able to keep their produce under the right conditions, leading to deterioration. This is especially important for perishable products like fruits and vegetables, which can spoil quickly if not kept in cool, dry places.

Furthermore, processing facilities are crucial for handling agricultural products soon after harvesting. Processing can include cleaning, sorting, drying, or packaging produce, which helps extend its shelf life and makes it ready for market. Without these facilities, produce can quickly degrade, resulting in significant wastage.

In summary, having sufficient and efficient storage and processing facilities is key to reducing wastage of agricultural products during the harvest period. It ensures that produce maintains its quality and can reach consumers without spoilage.

Gestation period is defined as the time

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The gestation period is defined as the period of time between conception and parturition. This means it is the duration from when an egg is fertilized by a sperm, leading to the formation of a fertilized egg, until the birth of the young animal. In humans, this period is typically about nine months. It is the time during which the embryo or fetus develops inside the mother's body, leading up to the birth.

Gummosis is caused by a

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Gummosis is a condition that affects trees, particularly stone fruit trees like peaches, cherries, and plums. It is characterized by the excretion of sap or gum from wounds or cracks in the bark. The primary cause of gummosis is often related to stress factors, injuries, or infections. While gummosis can occur due to a variety of reasons such as physical damage or environmental stress, it is important to understand the role of different organisms in causing or exacerbating this condition.

In the context of organisms that could be involved, **fungal** and **bacterial** infections are the most common biological causes of gummosis. **Fungal** infections such as those caused by the fungi of the genus Botryosphaeria, are frequently associated with gummosis in trees. These fungi invade the tree through wounds or damaged areas and result in the production of gum as the tree attempts to isolate the infection.

Similarly, **bacterial** infections, particularly by bacteria in the genus Pseudomonas (for example, Pseudomonas syringae), can also lead to gummosis. These bacteria take advantage of wounds to enter the tree and cause gum formation as a response to the infection.

Although **nematodes** and **viruses** can negatively impact trees, they are not typically associated with causing gummosis. **Nematodes** are more likely to affect the root system, while **viruses** might cause other symptoms like leaf mottling or fruit deformities.

Thus, **the most common biological causes of gummosis are infections by fungi and bacteria**. When dealing with gummosis, it is essential to examine the possible presence of these pathogens and address any injuries or stress factors affecting the tree.

Which of the following group of crops can be attacked by smut diseases?

Answer Details

Smut diseases are caused by a group of fungi that primarily attack cereal crops. The infection leads to the formation of thick-walled and often black, sooty spores. The crops most affected by smut diseases are those in the grass family. These fungi often attack the grains or inflorescences of the plants, which can lead to significant agricultural losses.

Out of the given options, the crops rice, maize, and guinea corn are susceptible to smut diseases. Here's why:

• Rice: Known to be affected by diseases such as kernel smut.
• Maize (corn): Commonly affected by common corn smut (Ustilago maydis), which is noted for its gall formations on ears and kernels.
• Guinea corn (Sorghum): Can suffer from several smut diseases including covered smut, loose smut, and head smut.

Therefore, rice, maize, and guinea corn form the group of crops that can be attacked by smut diseases.

An accessory sex gland in bull is

Answer Details

The accessory sex gland in a bull is the prostate gland.

The reproductive system in mammals includes various glands that support reproduction. In male animals like bulls, the accessory sex glands play a crucial role in the reproductive process:

• Prostate Gland: This is an important accessory sex gland in male mammals, including bulls. It produces a fluid that forms part of the semen. This fluid helps nourish the sperm and facilitates its movement. The prostate gland is specifically part of the male reproductive system.
• Thyroid Gland: This gland is located in the neck and regulates the body's metabolism by controlling the release of thyroid hormones. It is not involved in the reproductive system.
• Pancreatic Gland: This gland has both endocrine and exocrine functions, helping in digestion and regulation of blood sugar through insulin production. It is unrelated to reproduction.
• Pituitary Gland: Often referred to as the "master gland," it is situated in the brain and controls various other glands but is not directly an accessory gland in the reproductive system.

As we can see, the only gland in this list that is directly related to the reproductive system of bulls is the prostate gland. Therefore, it is the correct answer when identifying the accessory sex gland in bulls.

Which of the following soil water is tightly held to the surface of the soil particles?

Answer Details

The type of soil water that is tightly held to the surface of soil particles is hygroscopic water.

Here is a simple explanation:

• Hygroscopic water is so strongly attracted to the surface of soil particles that it forms a very thin film around them. This layer of water is held by strong forces of attraction called adhesive forces.
• This type of water is not available to plants because it is held too tightly for plant roots to extract it.
• Hygroscopic water is always present on soil particles, and even under very dry conditions, a certain amount of it remains attached to the particles.

In contrast, the other types of soil water, like capillary water and gravitational water, are less tightly bound and more available to plants or can be drained away under the force of gravity.

The correct sequence of the components of a goat's stomach is

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Goats, like other ruminants, have a unique digestive system adapted to break down fibrous plant material. Their stomach is divided into four compartments, each with specialized functions. Understanding the correct sequence of these compartments is crucial for comprehending how goats digest their food.

The correct sequence of a goat’s stomach is:

1. **Rumen**: This is the first and largest compartment. It serves as a fermentation vat where complex plant fibers are broken down by bacteria and other microorganisms. The rumen allows for the initial breakdown of food and is crucial for the digestion of cellulose found in plants.

2. **Reticulum**: Sometimes considered part of the rumen (together referred to as the reticulo-rumen), the reticulum works closely with the rumen. It traps foreign materials like small stones or metal objects and forms smaller food particles into cud, which are regurgitated back to the mouth for further chewing and digestion.

3. **Omasum**: This compartment acts as a filter. It absorbs water and minerals from the digested food and grinds the food particles further. The omasum has many folds, increasing its surface area to maximize absorption.

4. **Abomasum**: Known as the "true stomach," the abomasum is similar to a monogastric stomach (like in humans). It uses acids and digestive enzymes to break down proteins and complete the digestion process, preparing the food for intestines.

Thus, the correct sequence is rumen, reticulum, omasum, and abomasum.

A characteristic feature of subsistence agriculture is

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Subsistence agriculture is a type of farming where the primary aim is to produce enough food to meet the needs of the farmer's family, with little or no surplus for sale in the market. A characteristic feature of subsistence agriculture is the reliance on the supply of labor by farm families. This means that the farm work is primarily done by the family members themselves, and there is minimal use of hired labor.

In subsistence agriculture, the farmers often use traditional farming methods and tools, making family labor essential for farming activities. Unlike commercial agriculture, which focuses on maximizing production for sale, subsistence farming is primarily about meeting the family's food needs. As a result, the decisions on what to plant and how much to produce are driven by the household's consumption needs rather than market demands.

When a piece of land is leased to a farmer, the land is said to be

Answer Details

When a piece of land is leased to a farmer, the land is said to be allocated on a rental basis.

Let me explain further:

Leasing is a common agreement where the owner of a property (in this case, the land) grants someone else (the farmer) the right to use that property for a specified period. This does not involve buying the land; instead, the farmer pays a regular fee, often called rent, to the landowner.

In this arrangement, the landowner retains ownership of the land, and the agreement usually includes terms such as duration, financial compensation, and specific uses of the land. At the end of the lease, the land typically returns to the owner's control unless the lease is renewed.

Thus, leasing involves the use of the land under a rental agreement, not purchasing it, receiving it as a gift, or as a subsidy.

Which of the following processes does not lead to the physical disintegration of rock? 

Answer Details

The options provided refer to various processes that can affect rocks. To understand which process does not lead to the physical disintegration of rocks, let's explore each one clearly.

Expansion and contraction of rock minerals: This process refers to changes in the size of rock minerals due to temperature fluctuations. When minerals heat up, they expand, and when they cool down, they contract. Over time, this can cause the rock to crack and break apart. Therefore, this process does cause physical disintegration.

Formation of cracks and crevices in the rocks: This directly involves the breaking apart of rocks into smaller pieces due to the creation of openings or splits. Hence, it leads to physical disintegration.

Heating and cooling of rock surface: Rocks on the Earth's surface undergo cycles of heating during the day and cooling at night. These temperature variations cause the rock to expand and contract, similar to the effect on the rock minerals, eventually leading to cracking and breaking apart. Thus, this also causes physical disintegration.

Rapid cooling and solidification of rocks: This process typically refers to how molten rock (magma or lava) cools and hardens to form solid rock. When it cools rapidly, it solidifies quickly and forms a hard structure. This process does not involve breaking apart or physical disintegration of existing rock structures. Rather, it is about the formation of new rock. Therefore, this process does not result in the physical disintegration of rocks.

In conclusion, the process that does not lead to the physical disintegration of rock is the rapid cooling and solidification of rocks.

Igneous rocks formed within the crust are called

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Igneous rocks that form within the Earth's crust are called plutonic rocks. These rocks form when magma cools and solidifies slowly beneath the Earth's surface. Because of the slow cooling process, plutonic rocks typically have large, visible crystals. A common example of a plutonic rock is granite.

To better understand, imagine that magma is like a molten rock mixture. When it finds its way into the Earth's crust and cools down very slowly, it gives enough time for the crystals to grow large. This is different from volcanic rocks, which are formed when magma reaches the surface, cools quickly and forms smaller crystals.

A biotic factor influencing agricultural production is

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A **biotic factor** influencing agricultural production is a **predator**. Biotic factors are those that are living components in an ecosystem. In agriculture, predators, which include animals such as insects, birds, and mammals, can significantly affect crop yields. They influence the farming ecosystem by feeding on crops or on organisms that are beneficial or harmful to crops.

For instance, some predators might eat pests that could otherwise damage the plants, thereby indirectly helping in the production process. On the other hand, certain predators may attack the crops themselves, reducing yields. Therefore, understanding and managing **predator populations** is crucial in agricultural production to ensure crops are protected and can grow optimally.

The diagram above illustrates a reproductive process in a farm animal, study the process and answer the questions.

Which word best describes the process depicted by the diagram?

Answer Details

To explain this reproductive process comprehensively, let's break down each term and how it fits into the reproductive cycle of a farm animal.

Gestation: This is the period during which a female animal carries a developing embryo or fetus inside her body. In farm animals, gestation varies depending on the species. For example, the average gestation period for cows is about nine months, while for pigs it's around three months. During this phase, the female's body supports the developing young until birth.

Heat: Otherwise known as estrus, this is the period when a female animal is receptive to mating. It is part of the estrous cycle and signals that ovulation is about to occur. *During this time, the female exhibits specific behavioral changes that attract the male animal for breeding.

Ovulation: This is the process when the female's ovary releases an egg or ovum. It is a critical stage in the reproductive cycle because it's the time when fertilization by the male's sperm can occur. **Ovulation is timed with the heat period, making conception possible.**

Lactation: This is the period following birth during which a female animal produces milk. Lactation is essential for the nourishment and growth of the newborn. In many farm animals, lactation starts after parturition (birth) and continues for several months, providing the necessary nutrients for the offspring's development.

In conclusion, the reproductive process in farm animals involves a sequence of stages: **the female comes into heat and ovulates, potentially leading to conception.** If the egg is fertilized, the gestation period follows, culminating in birth, after which lactation begins to provide for the newborn. Each stage is meticulously timed and crucial for successful reproduction.

Although clay soil is rich in nutrients, they are not good for most agricultural crop production because

- They do not release their nutrients
- Are too compact
- Poorly aerated
- Contain too much iron, aluminum, and boron.
- Lose their nutrient too readily after rain.

Which of the above is most correct

Answer Details

Clay soil presents several challenges for agricultural crop production despite being rich in nutrients. One primary issue is that it often fails to release its nutrients effectively. The fine particles of clay hold onto nutrients too tightly, making it difficult for plant roots to absorb them. This means that although the nutrients are present, they are not always available to plants.

Another significant concern is that clay soil is too compact and poorly aerated. The tiny particles pack closely together, preventing air from circulating. This lack of aeration can lead to waterlogging, where plants cannot access oxygen needed for healthy root development. As a result, root systems can become weak and unable to support plant growth.

Additionally, clay soil may contain excessive amounts of iron, aluminum, and boron. While these elements are necessary in small quantities, their high levels can be toxic to plants, affecting their growth and development negatively.

Lastly, clay soil has a tendency to lose its nutrients readily after rain. Heavy rains can cause leaching, where water carries nutrients away from the root zone. Despite its nutrient richness, clay soil can become nutrient-deficient quickly after heavy rains, requiring frequent fertilization.

Overall, while clay soil is nutrient-rich, its composition and physical properties can significantly hinder crop production, making it less suitable for agriculture without proper management and amendment strategies.

Gneiss is a metamorphic rock formed from?

Answer Details

Gneiss is a type of metamorphic rock that primarily forms from the metamorphism of granite. Let's break this down to understand it better.

Metamorphic rocks are formed when existing rocks are subjected to high heat, high pressure, or chemically active fluids. This process, known as metamorphism, alters the mineral composition and structure of the original rock, also known as the parent rock or protolith.

Granite is an igneous rock composed mainly of quartz, feldspar, and mica. When granite undergoes metamorphism, typically deep within the Earth's crust where pressures and temperatures are high, it changes into a different kind of rock.

The specific conditions cause the minerals within the granite to align into bands or layers, giving gneiss its characteristic banded appearance. This banding is called "foliation."

While other types of rocks like slate, shale, and sandstone can also undergo metamorphism, they result in different metamorphic rocks. For instance:

• Slate forms from shale.
• Shale forms into slate and eventually into phyllite, schist, or gneiss under different conditions.
• Sandstone forms into quartzite.

In summary, gneiss is primarily the result of the metamorphism of granite.

The type of soil with a particle size of 0.02 to 0.002 mm

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The type of soil with a particle size ranging from 0.002 to 0.05 millimeters is known as silt. Soil particles are classified based on their sizes, and here is a brief explanation of other soil types for context:

• Clay: has very fine particles that are smaller than 0.002 millimeters. Clay particles are the smallest among soil types, creating a dense and sticky texture when wet.
• Silt: has slightly larger particles than clay, with sizes ranging from 0.002 to 0.05 millimeters. Silt feels smooth and floury to the touch and is less dense than clay.
• Fine Sand: consists of particles that are larger than silt, typically ranging from 0.05 to 0.2 millimeters. Fine sand has a gritty feel and allows water to drain through it more easily than silt or clay.
• Coarse Sand: contains even larger particles, generally ranging from 0.2 to 2 millimeters. It offers excellent drainage and is very gritty and rough to the touch.

In summary, silt describes soil with a particle size of 0.002 to 0.05 millimeters, making it distinct in its smooth texture and moderate drainage capacity.

Which of the following is an example of igneous rock?

Answer Details

The correct answer is granite. Let me explain why:

Igneous rocks are formed from the cooling and solidification of magma or lava. They are one of the three main types of rocks, the other two being sedimentary and metamorphic rocks. Now, let’s briefly look at the options:

• Granite is a classic example of an igneous rock. It forms from the slow cooling of magma beneath the Earth’s surface, which allows large crystals to develop. This process gives granite its distinctive, coarse-grained texture.
• Sandstone is not an igneous rock. It is a sedimentary rock, formed from compacted sand-sized mineral particles or rock fragments.
• Limestone is also a sedimentary rock, primarily made of calcium carbonate, which originates from biological sources like shells or coral.
• Gneiss is a metamorphic rock, which means it forms from existing rocks that have been transformed by heat and pressure. It is characterized by its banding and does not originate from cooling magma or lava.

Therefore, based on the formation and characteristics, granite is the example of an igneous rock in the list.

The horizon of the soil profile that encourages the greatest level of microbial activity is

Answer Details

The soil profile consists of different layers, known as horizons, each having distinct characteristics. The horizon where the greatest level of microbial activity occurs is the A-horizon. Let me explain why this is the case in a simple and comprehensive way.

The A-horizon is also known as the topsoil. It is the uppermost layer of the soil and is rich in organic material. This horizon contains **humus**, which is decomposed organic matter, making it very fertile. The reasons why microbial activity is so high in the A-horizon are:

• Rich in Organic Matter: The presence of decomposed organic material provides an excellent source of nutrients, which encourages the growth and activity of microbes such as bacteria, fungi, and actinomycetes.
• Favorable Conditions: The topsoil is well aerated and has good moisture content, which creates an optimum environment for microbial life.
• Presence of Plants: The root systems of plants are primarily located in the A-horizon. Root exudates provide additional nutrients that benefit microbial activity.

Overall, the combination of abundant organic material and favorable living conditions supports robust microbial communities in the A-horizon, making it the layer with the greatest microbial activity.

Plant breeders aim at obtaining the following except

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Plant breeders are focused on improving the characteristics of plants to meet specific goals and demands. Here is an explanation of the aims listed, highlighting the one that is generally not a typical aim for breeders:

Adaptation to pollination: Plant breeders generally focus on adaptations that allow for more efficient pollination. This could involve traits that attract pollinators or improve the chances of successful fertilization.

Tolerance to climate extremes: A significant aim for breeders is to develop plants that can withstand adverse climate conditions like drought, frost, or extreme temperatures. This ensures that the plants can survive and produce fruits or seeds even under challenging environments.

Uniformity in the time of maturity: Breeders aim for uniform maturity so that the entire crop can be harvested at the same time, simplifying the harvesting process and improving efficiency.

Resistance to pests: This is a critical aim because it reduces the need for pesticides, lowers production costs, and increases yield by ensuring that plants are less susceptible to diseases and pest attacks.

The point that is generally not a focus of plant breeders is adaptation to pollination specifically in terms of adapting plants for their own pollination processes. While pollination is important, breeders are more focused on traits that enhance successful pollination rather than altering the plant to adapt specifically for that process.

The alternate heating and cooling of rocks will result in

Answer Details

The **alternate heating and cooling of rocks** will primarily result in **fragmentation**. This process is commonly known as **physical weathering** or **mechanical weathering**.

Here's how it works:

• During the day, **rocks heat up due to sunlight**. This causes the outer layers of the rock to **expand**.
• At night, the **temperature drops**, causing the rock layers to **cool and contract**.
• This repeated process of expansion and contraction due to temperature changes creates **stress within the rock structure**.
• Over time, this stress causes the outer layers of the rock to **crack and break apart**, leading to **fragmentation** of the rock.

In contrast, the other processes listed involve different conditions:

• **Sublimation** refers to the direct transition of a substance from a solid to a gas, which is not relevant to rock weathering through temperature changes.
• **Solidification** involves the hardening of a substance from a liquid to a solid state, not fragmentation.
• **Molten magma** is formed under conditions of intense heat that melt rock into a liquid state, unrelated to the cooling process described above.

Thus, the **alternate heating and cooling of rocks** primarily results in their **fragmentation** into smaller pieces.

Air sacs are present in

Answer Details

Air sacs are present in poultry, which includes birds like chickens, ducks, and turkeys. These air sacs are an essential part of the avian respiratory system. Unlike mammals, birds have a unique respiratory system that includes a series of air sacs that facilitate a continuous flow of air through their lungs. This system allows for more efficient gas exchange, which is crucial for their energy needs during activities like flying.

In more detail, when birds inhale, air doesn't just go into their lungs but also fills these air sacs. On the next exhalation, the air moves from the air sacs into the lungs, where oxygen is exchanged for carbon dioxide. This method ensures that the bird's lungs have a continuous supply of fresh air, both when they inhale and exhale.

Other animals listed, such as rabbits, goats, and cattle, have different respiratory systems without air sacs; they rely on diaphragm-based breathing similar to humans for their oxygen needs. The specialized respiratory system of birds thus gives them an advantage in terms of metabolic efficiency, which is particularly important given the energy demands of flying.

Andropogon gayanus is commonly called

Answer Details

Andropogon gayanus is commonly called gamba grass.

The reason it is referred to as gamba grass stems from its characteristics and origin. Andropogon gayanus is a perennial grass species native to Africa, and it has been introduced to several other regions due to its usefulness as a cattle fodder because of its high biomass production and adaptability to different environments. Despite being beneficial for grazing, it can also become an invasive species in environments outside its native range. This characteristic name comes from its widespread and recognized use in agricultural and ecological contexts.

Which of the following processes will not lead to the loss of nutrients from the soil?

Answer Details

The process that will not lead to the loss of nutrients from the soil is mulching.

Here's a simple explanation of each process:

Leaching: This occurs when water (often from rain or irrigation) washes away nutrients from the soil into lower layers, making them unavailable to plants. This can result in a significant nutrient loss.

Harvesting: When crops are harvested, the nutrients that have accumulated in the plants' leaves, fruits, and other parts are removed from the environment, thus reducing the soil's nutrient content.

Erosion: This is the process where wind, water, or other natural agents wear away and move soil and its nutrients from one location to another, often leading to a reduction of soil fertility.

Mulching: This involves covering the soil with materials like straw, leaves, or wood chips. Mulching can help to retain soil moisture, reduce erosion, and enhance nutrient content as the mulch decomposes. Therefore, rather than causing nutrient loss, mulching adds nutrients back into the soil.

The replacement of traditional farming methods with modern methods is a step in agricultural

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The replacement of traditional farming methods with modern methods is a step in agricultural development. This is because development involves improving and advancing the way things are done to increase efficiency, productivity, and sustainability. By introducing modern methods, farmers can benefit from higher yields, better resource management, and improved quality of agricultural products.

Modern agricultural methods include the use of advanced technology such as tractors, automated machinery, and precision farming tools, as well as techniques like genetic modification and advanced irrigation systems. These methods help to optimize the use of resources, reduce the time and labor needed, and minimize environmental impact.

Traditional methods, on the other hand, often rely on manual labor and are subject to limitations such as low yields, more susceptibility to pests, and inefficient use of resources. By adopting modern techniques, agriculture becomes more efficient, sustainable, and capable of meeting the needs of a growing population.

Therefore, transitioning from traditional to modern methods is a sign of progress and development in agriculture.

The tree species commonly planted for pulpwood is

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When it comes to planting tree species for pulpwood, the primary goal is to select species that grow quickly and produce a high yield of wood fiber. **Gmelina arborea**, commonly referred to as Gmelina, is one of the most popular tree species used for this purpose. There are several reasons for this preference:

• Fast Growth Rate: Gmelina arborrea grows rapidly, which means it can be harvested sooner compared to other tree species. This makes it highly efficient for pulp production.
• High Wood Density: The wood from Gmelina is dense, providing a good quantity of pulp that is suitable for making paper and other pulp products.
• Adaptability: Gmelina can adapt to a variety of soil types and environmental conditions, making it a versatile choice for different geographic locations.
• Managing Soil Quality: It has been observed that Gmelina plantations can help in improving soil quality, which is beneficial for sustainable forestry practices.

These characteristics make **Gmelina arborea** an ideal choice for pulpwood production, allowing it to be favored in plantations focused on the production of pulp and paper products.

The most active agent of physical weathering in arid legions is

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In arid regions, the most active agent of physical weathering is wind.

Arid regions, known for their dry climates and minimal vegetation, provide ideal conditions for wind to actively erode and weather the landscape. Here's how it works:

• Loose Particles: The lack of vegetation means there is little to hold soil and small particles in place. This makes them easily picked up and carried by the wind.
• Abrasion: When wind carries particles like sand, they collide with rocks and surfaces, effectively sandblasting them. This process breaks down rocks into smaller pieces over time.
• Sculpting: Wind action can create unique rock formations as it wears away softer materials, leaving behind harder rock structures.
• Transportation: The wind can transport weathered material over long distances, affecting not just the source area but also where these particles are eventually deposited.

Although temperature, water, and ice can also contribute to physical weathering, wind is particularly significant in arid regions due to its persistence and effectiveness in altering the landscape without the need for much moisture.

Which of the following defines agriculture?

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Agriculture is best defined as the science and art of farming to satisfy human needs. This definition encompasses a broad range of activities that include both the cultivation of soil for growing crops and the raising of livestock. The concept of agriculture covers various aspects such as soil management, crop production, breeding, genetics, plant pathology, and more. It is both a science, because it involves understanding biological, chemical, and ecological processes, and an art, because it requires skill and expertise to effectively manage these processes to produce food and other resources needed by humans. Therefore, among the definitions provided, this one captures the full scope of what agriculture truly involves.

Which of the following uses of land should be given more attention in Nigeria for self-sufficiency in food production?

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In Nigeria, **establishing agriculture and forestry** should be given more attention to achieve self-sufficiency in food production. Here's why:

Agriculture:

• Nigeria has a vast stretch of arable land which can be utilized for growing diverse crops. By focusing on agriculture, the country can produce sufficient food to meet the local population's needs.
• Promoting agriculture leads to job creation, especially for the rural communities, thereby improving livelihoods.
• Expanding agricultural activities also boosts the local economy, reduces food importation, and fosters community development.

Forestry:

• Forestry complements agriculture by protecting the environment, preserving biodiversity, and maintaining the ecosystem balance.
• Trees improve soil fertility, which is essential for high crop yields and sustainable agriculture.
• Forestry can also provide additional resources, such as timber and non-timber forest products, further improving local economies.

While building research centers, establishing wildlife preserves, and constructing roads are essential in their own right, focusing on agriculture and forestry provides the foundation for ensuring food security, sustaining livelihoods, and fostering holistic economic growth in Nigeria.

The water-snail is important in the life cycle of

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The water-snail is important in the life cycle of the liver fluke. Liver flukes are parasitic flatworms that cause a disease called fascioliasis in the liver of various mammals, including humans, cattle, and sheep.

Here is a simple explanation of how the water-snail fits into the liver fluke's life cycle:

1. Egg Stage: The adult liver fluke lives in the host's liver and produces eggs, which are excreted in the host's feces.

2. Miracidium Stage: These eggs hatch in a water environment into larval forms called miracidia.

3. Snail Host: The miracidia must find and penetrate a specific species of freshwater snail. The water-snail serves as the intermediate host where the liver fluke undergoes a significant part of its development.

4. Sporocyst, Rediae, and Cercariae Stages: Inside the snail, the liver fluke develops through several stages: sporocysts, rediae, and cercariae.

5. Free-swimming Cercariae: The cercariae leave the snail and enter the water, seeking to attach to aquatic plants or other surfaces.

6. Metacercariae on Plants: The cercariae encyst to form metacercariae on these plants, waiting to be ingested by the next mammalian host.

Thus, the water-snail plays a crucial role as an intermediate host, enabling the fluke to transform into forms that are ready to infect mammals. Without the snail, the liver fluke's life cycle cannot continue.

One of the peculiarities of the intestine tract of a fowl is the possession of

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The intestinal tract of a fowl, like other avian species, has a peculiar feature known as the cloaca. This is a common cavity at the end of the digestive tract into which the intestinal, urinary, and reproductive tracts open. While many animals have separate openings for these systems, birds have a single opening called the cloaca.

The cloaca is a unique characteristic because it serves multiple functions. It receives waste from the intestines, urine from the kidneys, and eggs or sperm from the reproductive system. The cloaca then opens to the outside of the body, allowing the bird to excrete waste and reproduce.

This structure is different from mammals, which have separate systems for digestion, waste excretion, and reproduction. The cloaca is an efficient way for birds to streamline these processes, making it a distinctive and important feature of their anatomy.