JAMB Biology 2022 Past Questions & Answers

Air pollution is a significant ecological factor that affects living organisms and their environment. Sulphur dioxide is a gas released from industrial activities and burning fossil fuels. Vehicle exhausts release harmful gases like carbon monoxide and nitrogen oxides. Aerosols can release volatile organic compounds or CFCs, all contributing to air pollution.

Common mistake: Students might choose options like B or D because they contain some pollutants, but these options also include effects of pollution (e.g., acid rain) or pollutants primarily affecting water/soil (e.g., sewage, pesticides), rather than direct sources of air pollution.

The body of a snail, which is a mollusc, is distinctly divided into three main regions: the head, the visceral mass, and the foot. The head contains the mouth and sensory organs, while the visceral mass houses the internal organs. The muscular foot is responsible for locomotion, enabling the snail to move and providing support for its body.

Common mistake: Students often confuse the body divisions of a snail with those of insects (head, thorax, abdomen), leading them to incorrectly choose options containing 'thorax' or 'abdomen'.

The question asks for an adaptation specifically for defense in animals. Spines in a porcupine fish are a structural adaptation that deters predators, making it difficult for them to attack or eat the fish. This directly serves as a defense mechanism against ecological factors like predation, helping the organism survive in its environment.

Common mistake: Students might mistakenly choose options like 'huddling together of penguins' (D), which is primarily for warmth and social cohesion, or 'croaking of a male toad' (A), which is for attracting mates, not direct defense.

Tactic movement is the directional movement of an entire organism in response to an external stimulus like light. Euglena has a light-sensitive eyespot (stigma) which acts as a primitive sense organ, allowing it to detect the direction of light. The organism then moves its whole body towards the light to perform photosynthesis, which is a type of tactic movement called positive phototaxis.

Common mistake: Students often mistakenly choose 'tropic movement' because they associate light responses with phototropism, but tropism refers to directional growth in plants, not the movement of a whole organism like Euglena.

Metaphase is the stage of mitosis where the condensed chromosomes, each made of two sister chromatids, align themselves along the met metaphase plate, which is the imaginary equator of the cell. This precise alignment is crucial to ensure that each new daughter cell receives an identical set of chromosomes when they separate. Mitosis is a fundamental process for growth and development in multicellular organisms.

Common mistake: Students often confuse metaphase with anaphase, where the sister chromatids actually separate and move to opposite poles, rather than aligning at the equator.

Insects need to conserve water, so their excretory system removes nitrogenous waste as uric acid. Uric acid is a solid paste that requires very little water to be excreted, which is a key adaptation for survival in terrestrial environments.

Common mistake: Students often choose 'urine' because it is the common liquid excretory product in mammals, but insects excrete solid uric acid to conserve water.

Ecological succession is the process of change in an ecosystem over time. Secondary succession occurs in an area where an existing ecosystem has been disturbed, but the soil is still intact, like an abandoned farm or a place after a fire. Since the farm land already had life and soil, the new growth that happens there is an example of secondary succession.

Common mistake: Students often mistakenly choose 'primary succession' because they think 'abandoned' means starting from scratch, but primary succession only happens on brand new land with no soil.

Nigeria's vegetation is divided into different zones, or biomes, based on climate. The Southern Guinea Savanna is a major biome that acts as a transition zone between the southern rainforests and the drier northern savannas. States like Kogi and Kwara are located in the 'Middle Belt' of Nigeria, which falls squarely within this vegetation zone. Therefore, the Southern Guinea Savanna is the dominant vegetation type found in these states.

Common mistake: Students may mistakenly choose options with states from other savanna zones, like A (Borno and Sokoto) or D (Kano), because they forget that the Southern Guinea Savanna is specifically located in the Middle Belt, not the far north.

The dark stage of photosynthesis, also known as the Calvin cycle, is where carbon dioxide from the atmosphere is converted into glucose. This process is called carbon assimilation or carbon fixation, making option A the correct answer. The energy for this assimilation comes from the ATP and NADPH produced during the light stage.

Common mistake: Students often confuse the processes of the light and dark stages of photosynthesis. Options B, C, and D are all processes that occur during the light-dependent stage, not the dark stage.

The skin is considered an accessory excretory organ in mammals. The sweat gland, found in the dermis layer of the skin, is responsible for producing sweat. Sweat is primarily water but also contains metabolic wastes like urea, salts, and uric acid, which are then removed from the body when sweat is released onto the skin's surface.

Common mistake: Students often confuse the sweat gland with the sebaceous gland, but the sebaceous gland's main function is to secrete sebum (oil) for lubrication, not to excrete metabolic wastes like urea.