2025 - JAMB Biology Past Questions and Answers - page 10

In an ecosystem, organisms depend on one another for food, and energy moves from one organism to another when feeding occurs. While a single pathway showing who eats whom is called a food chain, natural ecosystems usually have many interconnected feeding relationships.

Most organisms eat more than one type of food and may also be eaten by several predators. This creates multiple overlapping food chains that connect together. These interconnected feeding pathways form a network that illustrates the flow of energy through many organisms.

This network showing numerous feeding relationships and energy transfer within a habitat is known as a food web.

Therefore, the correct answer is food web.

A reflex action is an automatic and rapid response to a stimulus that occurs without conscious control. It helps protect the body from harm and is controlled by a reflex arc involving sensory nerves, the spinal cord or brain, and motor nerves.

When an irritant such as dust or smoke enters the respiratory tract, receptors detect it and immediately send signals through nerves to trigger a response. The body responds by forcefully expelling air to remove the irritant.

This response happens quickly and automatically without the need for conscious decision-making. Such an involuntary protective response is known as coughing.

Therefore, the correct answer is coughing.

Wind dispersal occurs when plant fruits or seeds are carried away by air currents. For wind dispersal to be effective, the structure must be light and often possess features that allow it to be carried easily by air.

A cypsela is a type of dry fruit that contains a single seed. It often has fine hair-like or feathery structures attached to it, which increase its surface area. This makes it easier for the wind to lift and transport the fruit over long distances.

Because of this special adaptation, the cypsela can be dispersed efficiently by wind.

Therefore, the correct answer is cypsela.

Bats belong to the group of animals known as mammals, while birds belong to a different group called aves. Mammals have special glands known as mammary glands that produce milk for feeding their young.

After giving birth, female bats nourish their offspring with milk produced from these glands. This is a defining feature of all mammals.

Birds, on the other hand, do not have mammary glands. Instead, they feed their young using other methods such as regurgitated food.

This difference clearly separates bats from birds.

Therefore, the correct answer is possess mammary glands.

Proteins are complex biological molecules that perform many important functions in living organisms, such as building tissues and acting as enzymes.

These large molecules are formed by linking many smaller molecules together in a chain. The smaller units that join together to form proteins are called amino acids.

Each amino acid contains specific chemical groups that allow them to bond with one another. When many amino acids join through peptide bonds, they form a long chain called a polypeptide, which folds into a functional protein.

Therefore, the smaller units that make up proteins are amino acids.

Therefore, the correct answer is amino acids.

The organ level of organization refers to a structure made up of different tissues working together to perform a specific function.

In plants, organs include structures such as roots, stems, and leaves. These organs consist of various tissues such as epidermal tissue, vascular tissue, and storage tissue, all working together.

An onion bulb is an example of a plant organ because it contains different tissues that function together mainly to store food and support plant growth.

This confirms that the onion bulb exists at the organ level of organization.

Therefore, the correct answer is Onion bulb.

The carbon cycle describes how carbon moves between the atmosphere, living organisms, and the environment. Carbon exists in the atmosphere mainly as carbon dioxide.

When organic materials such as wood, coal, or fossil fuels burn, the carbon stored in them combines with oxygen. This reaction produces carbon dioxide, which is released into the atmosphere.

This burning process is known as combustion, and it plays an important role in returning carbon to the atmosphere.

Therefore, the correct answer is Combustion.

The calyx is the outermost part of a flower and is made up of structures called sepals. These sepals protect the flower when it is still in the bud stage.

In some flowers, the sepals remain separate from each other. In other flowers, the sepals are joined together to form a single united structure.

When the sepals are fused into one continuous structure, this condition is described using the term gamosepalous.

Therefore, the correct answer is gamosepalous.