WAEC Biology 2023 past questions

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

Ten questions from the 2023 WAEC Biology paper, with answers and explanations. We hold 55 questions from this paper, and the Skolra app has all of them.

WAEC Biology 2023 questions and answers

1. 1.

   The eye defect caused by an uneven curvature of the cornea or lens or both is

   1. A
      Presbyopia
   2. B
      Myopia
   3. C
      Astigmatism
      Correct
   4. D
      Hyperopia
   Show answerHide answer

   Answer: C

   Astigmatism is the eye defect caused by uneven curvature of the cornea or lens, or sometimes both. This irregular curvature causes light rays to focus at multiple points on the retina rather than a single focal point, resulting in blurred vision at all distances. Unlike myopia (short-sightedness) or hyperopia (long-sightedness), which involve overall focusing problems, astigmatism involves distorted focus due to asymmetrical curvature.
2. 2.

   The rate of decomposition of dead organisms is faster in the tropical rainforest than in other biomes because

   1. A
      More decomposers are present
   2. B
      The soil is more acidic
   3. C
      There is abundant leaf litter
   4. D
      Temperature and humidity are high
      Correct
   Show answerHide answer

   Answer: D

   Decomposition is faster in tropical rainforests because the high temperature and high humidity create ideal conditions for decomposer activity. Decomposing bacteria and fungi work fastest in warm, moist environments (20-30°C and near 100% humidity). While other factors like high decomposer populations and abundant leaf litter also contribute, the primary abiotic factors are temperature and humidity, which directly affect enzyme activity and microbial metabolism rates.
3. 3.

   A sudden change in the genetic composition of an organism is termed

   1. A
      Adaptation
   2. B
      Mutation
      Correct
   3. C
      Evolution
   4. D
      Natural selection
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   Answer: B

   A mutation is a sudden, random change in the DNA sequence of an organism's genes, resulting in a change in genetic composition. Mutations can be spontaneous (due to copying errors during DNA replication) or induced (by radiation or chemicals). While adaptation and evolution involve genetic changes over time through natural selection, mutation specifically refers to the sudden alteration in genetic material itself.
4. 4.

   A group of organisms belonging to different species that coexist in the same habitat and interact is referred to as

   1. A
      Biome
   2. B
      Ecosystem
   3. C
      Community
      Correct
   4. D
      Population
   Show answerHide answer

   Answer: C

   A community consists of all the different species of organisms living and interacting in the same habitat. It represents the biotic (living) component of an ecosystem. A population is a group of organisms of the same species in the same area; an ecosystem includes the community plus the abiotic (non-living) factors; a biome is a large geographic region with similar climate and organisms. The community specifically emphasizes the interaction of multiple different species.
5. 5.

   Which of the following processes does not occur during photosynthesis?

   1. A
      Release of carbon dioxide
      Correct
   2. B
      Synthesis of glucose
   3. C
      Release of oxygen
   4. D
      Absorption of light energy
   Show answerHide answer

   Answer: A

   Carbon dioxide is absorbed (not released) during photosynthesis. In the light-dependent reactions, light energy is absorbed by chlorophyll and used to split water, releasing oxygen as a byproduct. In the light-independent (Calvin) reactions, carbon dioxide is fixed and reduced to form glucose. Therefore, photosynthesis absorbs CO₂ and releases O₂, making carbon dioxide release incorrect for this process.
6. 6.

   The structure that its action could result in choking when talking and eating at the same time is

   1. A
      Trachea
   2. B
      Esophagus
   3. C
      Pharynx
   4. D
      Epiglottis
      Correct
   Show answerHide answer

   Answer: D

   The epiglottis is a flap-like cartilaginous structure that covers the entrance to the trachea (windpipe) during swallowing, preventing food from entering the respiratory tract. However, if you talk while eating, you may lower the epiglottis prematurely or not seal it properly, allowing food to enter the trachea instead of the esophagus, causing choking or aspiration. The epiglottis's failure to properly seal the airway during concurrent swallowing and vocalization is the direct cause of choking in this scenario.
7. 7.

   Which of the following activities is against the conservation of natural resources?

   1. A
      Crop rotation
   2. B
      Reforestation
   3. C
      Sustainable harvesting
   4. D
      Indiscriminate hunting
      Correct
   Show answerHide answer

   Answer: D

   Indiscriminate hunting (killing animals without regulation or limits) is against conservation of natural resources because it depletes wildlife populations faster than they can reproduce, leading to species extinction and ecosystem imbalance. Conservation requires regulated hunting with quotas, reforestation to replace harvested trees, and sustainable practices. Activities like crop rotation and sustainable harvesting maintain resource productivity for future use, while indiscriminate hunting destroys biological diversity and threatens species survival.
8. 8.

   Which of the following organisms would be the producer in a food chain?

   1. A
      Bacteria
   2. B
      Green plant
      Correct
   3. C
      Grasshopper
   4. D
      Lion
   Show answerHide answer

   Answer: B

   Green plants are the primary producers in food chains because they synthesize organic compounds from inorganic substances (CO₂ and H₂O) using light energy through photosynthesis. All other organisms (grasshopper, lion, bacteria) are consumers or decomposers that depend on organic matter produced by plants. Producers form the base of all food chains and food webs, converting solar energy into chemical energy stored in organic molecules.
9. 9.

   a.Relationships I, II, III, IV and V exist among some organisms in an ecosystem. Use them to answer the question
   I: Organism A grows on dead organism B.
   II: Organism C feeds on the remnants of food left by organism D without affecting organism D negatively or positively
   III: Organism E provides shelter for organism F while organism F transports organism E towards food
   IV: Organism G kills organism B for food
   V: Organism H feeds on organism J, causing organism J a disease.
   
   Name the type of relationship in: I,II,III,IV,V

   b. what is the biological term for each of organisms B and G?

   c. Name one example each of organisms B to J

   di. Name the relationship that is most beneficial to the ecosystem.

   ii Give one reason for the answer in 3d(i)

   ei. Give two examples of organism A

   ii. Name the group to which organism A belongs

   1. A
      I-parasitism, II-competition, III-mutualism, IV-predation, V-commensalism
      Correct
   2. B
      I-saprophytism, II-predation, III-commensalism, IV-parasitism, V-mutualism
   3. C
      I-competition, II-parasitism, III-commensalism, IV-mutualism, V-predation
   4. D
      I-saprophytism, II-commensalism, III-mutualism, IV-parasitism, V-predation
   Show answerHide answer

   Answer: A

   Relationship I (A grows on dead B) is saprophytism/decomposition. Relationship II (C feeds on food remnants without affecting D) is commensalism. Relationship III (E provides shelter and F transports E) is mutualism. Relationship IV (G kills B for food) is predation. Relationship V (H feeds on J causing disease) is parasitism. These ecological relationships describe how organisms interact in ecosystems.
10. 10.

    The capturing and digestion of insects by a pitcher plant is a special form of nutrition that is

    1. A
       Saprotrophic nutrition
    2. B
       Insectivorous nutrition
       Correct
    3. C
       Parasitic nutrition
    4. D
       Chemosynthetic nutrition
    Show answerHide answer

    Answer: B

    Insectivorous (or carnivorous) nutrition is the specialized form of heterotrophic nutrition where organisms capture and digest insects or other small animals for nutrients. Pitcher plants use modified leaves that trap insects in a digestive fluid containing enzymes. This is an adaptation for obtaining nitrogen and other nutrients in poor, acidic soils where plants cannot absorb sufficient minerals.

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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