WAEC Biology past questions and answers

Checked by the Skolra question team · Last updated 15 October 2026

WAEC Biology: 1,517 objective past questions from 26 papers between 1998 and 2023, each with the answer and an explanation. Here are ten.

How the WAEC Biology paper is set. On WAEC's 2026 timetable for private candidates, Paper 1 (objective) takes 50 minutes, Paper 2 (essay) 1 hour 40 minutes and Paper 3 (alternative to practical work) 2 hours. If the question paper on the day gives another time, follow the question paper. The questions here are from Paper 1.

1. 1.Green plants lose water to the atmosphere through the process of
   1. A
      guttation
   2. B
      transpiration
      Correct
   3. C
      excretion
   4. D
      respiration
   Show answerHide answer

   Answer: B

   Transpiration is the process by which green plants lose water vapour to the atmosphere, primarily through stomata on the leaf surface, but also through the cuticle and lenticels. It is driven by the evaporation of water from mesophyll cells and creates a tension that helps draw water up through the xylem (the transpiration stream). Guttation involves the loss of liquid water through hydathodes and occurs under specific conditions, not the primary route of water loss.

2. 2.

   Organisms that feed on dead, decaying tissues of other organisms are known as

   1. A
      Parasites
   2. B
      Saprophytes
      Correct
   3. C
      Herbivores
   4. D
      Predators
   Show answerHide answer

   Answer: B

   Saprophytes (or saprotrophs) are organisms that feed on dead, decaying organic matter and tissues of other organisms. They absorb nutrients from decomposing material through extracellular digestion, playing a crucial role in nutrient cycling and ecosystem health. Common saprophytes include bacteria, fungi, and some molds. They are distinct from parasites (which feed on living hosts), predators (which hunt and kill prey), and herbivores (which feed on living plants).
3. 3.

   Which of the following materials is not easily biodegradable?

   1. A
      Food waste
   2. B
      Faecal matter
   3. C
      Fallen leaves
   4. D
      Plastic bags
      Correct
   Show answerHide answer

   Answer: D

   Biodegradable materials are broken down by microorganisms (bacteria and fungi) into simpler inorganic substances. Fallen leaves, faecal matter, and food waste are all organic materials readily decomposed by decomposers. Plastic bags are synthetic polymers that resist microbial degradation and may persist in the environment for hundreds to thousands of years, making them not easily biodegradable and a major environmental pollutant.
4. 4.The function of the red blood cells is to
   1. A
      Fight pathogens and foreign bodies
   2. B
      Initiate clotting to seal wounds
   3. C
      Transport oxygen to body tissues
      Correct
   4. D
      Produce antibodies for immunity
   Show answerHide answer

   Answer: C

   The primary function of red blood cells (erythrocytes) is to transport oxygen from the lungs to all body tissues. They contain the pigment haemoglobin, which binds to oxygen in the lungs to form oxyhaemoglobin and releases it in tissues where oxygen concentration is low. Red blood cells also carry some carbon dioxide back to the lungs.

5. 5.In the test for starch, the leaf is first placed in boiling water to
   1. A
      Extract starch from the leaf
   2. B
      Make the leaf transparent
   3. C
      Remove chlorophyll from the leaf
   4. D
      Kill the cells and stop enzyme activity
      Correct
   Show answerHide answer

   Answer: D

   In the starch test, the leaf is first placed in boiling water to kill the cells and stop all enzyme activity, preventing further biochemical changes. This step also softens the leaf and makes it more permeable. Chlorophyll is removed in the next step by boiling in alcohol (ethanol), which decolourises the leaf so that iodine solution can react with any starch present.

6. 6.The major problem experience by organisms living in small water bodies is
   1. A
      Excessive food competition from large predators
   2. B
      Consistently high levels of dissolved oxygen
   3. C
      Extremely low temperature fluctuations throughout the year
   4. D
      Rapid and extreme changes in environmental conditions such as temperature, salinity and pH
      Correct
   Show answerHide answer

   Answer: D

   Small water bodies such as ponds and rock pools have a small volume of water relative to their surface area, which means that environmental conditions can change rapidly and dramatically. Temperature may rise sharply on a hot day and fall overnight, dissolved oxygen can be depleted quickly, and salinity and pH can shift significantly after rainfall or evaporation. These rapid fluctuations create a harsh and unpredictable habitat that organisms must be specifically adapted to tolerate. Large water bodies such as oceans and lakes have greater thermal stability and buffer capacity, making them more stable environments for a wider range of life.
7. 7.The basis of growth involves the following processes except
   1. A
      Cell elongation and increase in cell size
   2. B
      Cell division by mitosis to increase cell number
   3. C
      Cell differentiation into specialized cell types
   4. D
      Excretion of metabolic waste products from body cells
      Correct
   Show answerHide answer

   Answer: D

   Growth in living organisms is based on three processes: cell division (mitosis) to increase cell number, cell enlargement (elongation) to increase cell size, and cell differentiation whereby cells become specialized for particular functions. Excretion is the removal of metabolic waste products such as urea and carbon dioxide from the body, and while it is a necessary life process, it does not contribute to increasing body size or the production of new tissues. Excretion is therefore not a basis of growth.

8. 8.

   (a) Describe the carbon cycle.

   (b) State the functions of:
   (i) nitrogen fixing bacteria
   (ii) nitrifying bacteria
   (iii) denitrifying bacteria; in nature.
   

   1. A
      Decomposition of organic matter by bacteria and fungi
   2. B
      Aerobic respiration by animals and plants
   3. C
      Combustion of fossil fuels such as coal and petroleum
   4. D
      Photosynthesis by green plants and other autotrophs
      Correct
   Show answerHide answer

   Answer: D

   During the carbon cycle, carbon dioxide is removed from the atmosphere principally by photosynthesis, in which green plants use CO₂, water and sunlight energy to manufacture glucose. This locks atmospheric carbon into organic molecules. Respiration, decomposition and combustion are processes that return carbon dioxide to the atmosphere, completing the cycle rather than removing it.

9. 9.Which of the following features enables the tapeworm to live successfully in the small intestine of human?
   1. A
      Absence of a digestive system and direct absorption of digested food through the body surface
      Correct
   2. B
      A thick muscular body wall that resists digestive enzymes of the host
   3. C
      A well-developed digestive system for processing nutrients rapidly
   4. D
      Photosensitive cells that detect movement within the host gut
   Show answerHide answer

   Answer: A

   The tapeworm (Taenia) is highly adapted for endoparasitic life in the small intestine. It has completely lost its digestive system through evolutionary regression and instead absorbs pre-digested nutrients directly through its tegument (body wall), which is richly supplied with microvilli. It also possesses hooks and suckers on its scolex (head) for firm attachment to the intestinal lining. Its proglottids produce enormous quantities of eggs, greatly increasing the probability of transmission to a new host.

10. 10.

    The scientist who introduced binomial nomenclature in the classification of organisms was

    1. A
       Charles Darwin
    2. B
       Robert Hooke
    3. C
       Carolus Linnaeus
       Correct
    4. D
       Gregor Mendel
    Show answerHide answer

    Answer: C

    Carolus Linnaeus (Carl von Linné, 1707–1778) developed the system of binomial nomenclature, in which every species is given a two-part Latin name — the first part is the genus and the second is the species epithet (e.g., Homo sapiens). He formalised this system in Species Plantarum (1753) and Systema Naturae. This standardised naming system allows scientists worldwide to communicate unambiguously about organisms. Darwin contributed evolutionary theory; Hooke discovered cells; Mendel established genetics — none introduced binomial nomenclature.

The questions come from past JAMB, WAEC and NECO papers. We use software to help write the answer options and explanations, and every answer is checked twice before it goes on the site. How we check

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