WAEC (WASSCE) Biology Past Questions and Answers (2026)

Answer: C

The correct answer is C because the function of a multicellular organism is indeed the sum total of the functions of its constituent cells, meaning that each cell contributes to the overall functioning of the organism. Option A is incorrect because while multicellular organisms are made up of cells, this alone does not explain why the cell is a functional unit. Option B is misleading as it suggests that all cells function as a single cell, which is not accurate; cells have specialized functions. Option D is incorrect because it implies that a single cell's function is superior, which is not true in the context of multicellular organisms. Option E is also incorrect because while cells may share similarities, they can also differ significantly in structure and function depending on their roles within the organism.

Answer: B

The contractile vacuole is an organelle found in many protozoa that functions to expel excess water from the cell, helping to maintain osmotic balance. The plasma membrane is responsible for regulating the entry and exit of substances but does not specifically eliminate water. The cell wall provides structural support and protection but does not play a role in water elimination. Protoplasm refers to the living contents of a cell, and the nucleus is involved in genetic control and cell regulation, neither of which are related to water elimination.

Answer: A

Spirogyra is considered multicellular because its cells are connected by cytoplasmic strands, allowing for communication and nutrient sharing between them. Option B is incorrect because Spirogyra does not form true organs. Option C is misleading; while the cells are cylindrical and can be linked end to end, this alone does not define multicellularity. Option D is incorrect as it states that the filaments consist of one cell only, which is false; Spirogyra is filamentous and consists of multiple cells. Option E is incorrect because being an alga with large vacuoles does not determine its multicellularity.

Answer: C

The mechanism of gaseous exchange in living organisms primarily occurs through diffusion, which is the movement of molecules from an area of higher concentration to an area of lower concentration. In the context of gaseous exchange, oxygen diffuses from the alveoli in the lungs (where its concentration is high) into the blood (where its concentration is lower), while carbon dioxide diffuses in the opposite direction. Osmosis (Option A) refers to the movement of water across a semi-permeable membrane and is not directly related to gaseous exchange. Inhalation (Option B) and exhalation (Option D) are parts of the breathing process but do not describe the underlying mechanism of gas exchange itself. Breathing (Option E) encompasses inhalation and exhalation but again does not specifically address the diffusion process that allows for gas exchange at the cellular level.

Answer: B

The correct answer is B because diffusion is the process where molecules move from an area of higher concentration to an area of lower concentration, which is driven by the concentration gradient. Option A is incorrect because diffusion involves the movement of all types of molecules, not just water. Option C is incorrect because diffusion can occur without a differentially permeable membrane; it can happen in open spaces as well. Option D is incorrect as it misrepresents the process of diffusion; diffusion does not require a solute to be unable to dissolve. Option E is also incorrect as it describes a situation that is not related to the definition of diffusion.

Answer: B

The correct answer is B, fermentation, because it specifically refers to the anaerobic process by which yeast converts sugars into alcohol and carbon dioxide. Option A, oxidation, is incorrect as it generally refers to the loss of electrons in a chemical reaction, not specifically related to yeast. Option C, tissue respiration, refers to aerobic respiration in cells, which is not applicable here. Option D, alcohol production, while related, is not the specific term for the process. Option E, decomposition, involves the breakdown of organic matter, which is not the same as fermentation.

Answer: E

The skeleton provides support for the body (A), protects delicate internal organs (B), maintains the shape of the body (C), and provides attachment for muscles (D). However, it does not control growth rate in animals (E), which is primarily regulated by hormones and other biological processes.

Answer: D

Muscles are attached to bones by tendons, which are strong, flexible connective tissues that transmit the force generated by muscles to the bones, enabling movement. Ligaments (Option A) connect bones to other bones, not muscles to bones. Cartilage (Option B) provides cushioning between bones but does not attach muscles. The synovial membrane (Option C) lines joint cavities and produces synovial fluid for lubrication, but it does not connect muscles to bones. Connective tissue (Option E) is a broad category that includes tendons but is not specific enough to be the correct answer.

Answer: B

In monocotyledons, the stem and root do not have cambium, which is a layer of actively dividing cells that contributes to secondary growth. Instead, monocots typically exhibit primary growth only. Xylem (A), pith (C), cortex (D), and pericycle (E) are all present in monocot stems and roots, making them incorrect options.

Answer: B

The pulmonary vein carries oxygenated blood from the lungs to the left auricle, which is essential for delivering oxygen-rich blood to the body. Option A is incorrect because the right ventricle pumps deoxygenated blood to the lungs via the pulmonary artery, not the pulmonary vein. Option C is incorrect as it states that the pulmonary vein carries deoxygenated blood, which is false. Option D is incorrect because the pulmonary vein does not carry blood to the right auricle; it carries oxygenated blood to the left auricle. Option E is incorrect as it describes the function of the pulmonary artery, which carries deoxygenated blood from the right ventricle to the lungs.

Answer: C

The larynx is the upper part of the trachea in mammals and is responsible for sound production and protecting the airway during swallowing. The palate (A) is the roof of the mouth, not part of the trachea. The epiglottis (B) is a flap that covers the larynx during swallowing but is not the upper part of the trachea itself. The glottis (D) refers to the opening between the vocal cords within the larynx, and the bronchus (E) is a branch of the trachea that leads to the lungs, not the upper part of the trachea.

Answer: B

The sweat gland is directly involved in excretion as it helps in the removal of waste products like urea and salts through sweat. The sebaceous gland secretes oil to lubricate the skin, but it does not play a role in excretion. The horny layer (stratum corneum) is the outermost layer of skin that provides protection and does not participate in excretion. The hair follicle is involved in hair growth and does not contribute to excretion. The Malpighian layer (stratum basale) is responsible for the generation of new skin cells and is not involved in excretion.