WAEC Biology 2012 past questions

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

Ten questions from the 2012 WAEC Biology paper, with answers and explanations. We hold 68 questions from this paper, and the Skolra app has all of them.

WAEC Biology 2012 questions and answers

1. 1.

   Which of the following digestive enzymes would be greatly affected if the liver fails to

   Produce bile?

   1. A
      Lipase
      Correct
   2. B
      Salivary amylase
   3. C
      Pepsin
   4. D
      Maltase
   Show answerHide answer

   Answer: A

   Bile is a digestive secretion produced by the liver and stored in the gallbladder. It contains bile salts that emulsify fats — breaking large fat globules into tiny droplets, increasing their surface area for enzymatic digestion. Lipase (secreted by the pancreas and small intestinal wall) digests fats (triglycerides) into fatty acids and glycerol and depends on bile for efficient emulsification. Without bile, fat digestion is severely impaired. Salivary amylase digests starch, pepsin digests proteins in the stomach, and maltase digests maltose — none of these enzymes act on fats and are unaffected by absent bile production.

2. 2.

   Which of the following food substances will have

   Little or no calorific value?

   1. A
      Fats and oils
   2. B
      Mineral salts and vitamins
      Correct
   3. C
      Proteins
   4. D
      Carbohydrates
   Show answerHide answer

   Answer: B

   Mineral salts (e.g., iron, calcium, sodium) and vitamins do not provide energy (calories) when metabolised. They are classified as micronutrients that serve regulatory and structural roles — minerals build bones and teeth, maintain nerve function and water balance, while vitamins act as coenzymes in metabolic reactions. Fats have the highest calorific value (approximately 37 kJ/g), carbohydrates and proteins each yield approximately 17 kJ/g. Foods are considered 'caloric' only if they contain energy-releasing macronutrients; minerals and vitamins are essential but not energy-yielding nutrients.

3. 3.Which of the following diseases is transmittable through genes?
   1. A
      Sickle cell anaemia
      Correct
   2. B
      Typhoid fever
   3. C
      Tuberculosis
   4. D
      Malaria
   Show answerHide answer

   Answer: A

   Sickle cell anaemia is an inherited (genetic) disease caused by a mutation in the haemoglobin gene, resulting in abnormal haemoglobin S. It is transmitted from parents to offspring through genes following an autosomal recessive inheritance pattern — a child inherits two copies of the sickle cell gene (one from each parent) to be affected. It cannot be acquired from another person or through the environment. Malaria is caused by Plasmodium parasites transmitted by mosquitoes. Tuberculosis is caused by Mycobacterium tuberculosis spread through airborne droplets. Typhoid fever is caused by Salmonella typhi spread through contaminated food and water.

4. 4.

   LIST OF SPECIMENS PROVIDED

   SPECIMEN A: GARDEN EGG
   SPECIMEN B: TRIDAX FRUIT
   SPECIMEN C: GRAIN WEEVIL
   SPECIMEN D: TICK
   SPECIMEN E: RAT/GUINEA PIG
   SPECIMEN J: TILAPIA FISH (WET PRESERVED)
   SPECIMEN K: TOAD (WET PRESERVED)
   SPECIMEN L: LIZARD (WET OR DRY PRESERVED)

   Study carefully specimens C, D and E and use them to answer questions 2(a) to 2(c).

   (a) (i) State the mode of nutrition of specimen D.

   (ii) State one way by which each of specimens C, D and E is of economic importance.

   (b)(i) Classify specimens C, D and E into their phyla and classes.

   (ii) List three observable characteristic features of each of the classes to which specimens C, D and E belong.

   (iii) In a tabular form, state two observable differences between C and D.

   (C) List four observable features of specimen E that are sensory in nature.

   1. A
      Arachnida, Insecta, Mammalia
   2. B
      Crustacea, Arachnida, Reptilia
   3. C
      Insecta, Arachnida, Insecta
   4. D
      Insecta, Arachnida, Mammalia
      Correct
   Show answerHide answer

   Answer: D

   Specimen C (Grain weevil) belongs to class Insecta because it has three pairs of legs, three body segments (head, thorax, abdomen) and one pair of antennae. Specimen D (Tick) belongs to class Arachnida because it has four pairs of legs, two body segments (cephalothorax and abdomen) and no antennae. Specimen E (Rat/Guinea pig) belongs to class Mammalia because it has hair/fur, gives birth to live young, and suckles its young with milk. The phylum for C and D is Arthropoda, while E belongs to phylum Chordata.

5. 5.

   A space containing a group of interactive organisms

   Is called

   1. A
      A habitat
   2. B
      An ecosystem
      Correct
   3. C
      A population
   4. D
      A biome
   Show answerHide answer

   Answer: B

   An ecosystem is defined as a functional unit comprising a community of organisms (biotic components) interacting with each other and with their non-living environment (abiotic components) within a defined space. Energy flows and nutrients cycle within an ecosystem. A population is all individuals of one species in a given area. A habitat is the specific place where an organism lives. A biome is a large-scale ecosystem characterised by dominant vegetation and climate. The key features of an ecosystem are the presence of producers, consumers, decomposers, and abiotic factors all interacting together.

6. 6.Increasing adrenalin content of the blood would be expected to decrease the flow of blood to the
   1. A
      Heart muscle
   2. B
      Digestive system
      Correct
   3. C
      Skeletal muscles
   4. D
      Brain
   Show answerHide answer

   Answer: B

   Adrenalin (epinephrine) is the 'fight or flight' hormone released by the adrenal medulla in response to stress or danger. It prepares the body for rapid action by increasing heart rate, dilating blood vessels in the skeletal muscles, heart and brain to supply them with more oxygen and glucose. To achieve this, blood is diverted away from the digestive system by constricting the blood vessels supplying the gut and visceral organs. This is why intense fear or exercise suppresses digestive activity. The digestive system is a non-essential organ during emergencies and receives decreased blood flow under adrenalin stimulation.

7. 7.Squirrels easily kill some trees because
   1. A
      They eat all the leaves preventing photosynthesis entirely
   2. B
      They bore into the heartwood and introduce decay fungi
   3. C
      They strip the bark in a ring around the trunk, cutting off the phloem
      Correct
   4. D
      They damage the roots by burrowing near the base of trees
   Show answerHide answer

   Answer: C

   Squirrels kill trees by girdling — stripping bark in a complete ring around the trunk. The bark contains the phloem, which transports sugars manufactured in the leaves downward to the roots. When phloem is completely removed in a circle, food cannot reach the roots, which eventually starve and die. Once roots die, the tree can no longer absorb water and minerals, killing the entire tree. This is different from partial bark damage, which allows healing. The process of girdling a tree to kill it is also intentionally used in forestry to clear unwanted trees without felling them.

8. 8.Plants with breathing roots are characteristic features of vegetation in
   1. A
      Mangrove swamps
      Correct
   2. B
      Desert regions
   3. C
      Tropical rainforests
   4. D
      Savanna grasslands
   Show answerHide answer

   Answer: A

   Breathing roots (pneumatophores) are specialised aerial roots that grow upward out of waterlogged, anaerobic soil to obtain oxygen for root respiration. They are characteristic of plants in mangrove swamps — coastal wetlands with brackish water and oxygen-depleted mud. Mangrove trees such as Rhizophora and Avicennia have evolved pneumatophores to survive in environments where the soil contains virtually no free oxygen. Tropical rainforest soils, while sometimes waterlogged, do not consistently have the extreme anaerobic conditions of mangrove swamps. Desert and savanna plants face completely different challenges (drought, not waterlogging).

9. 9.When fertilization occurs that leads to formation of a zygote, which of the following processes takes place?
   1. A
      Meiotic division of the egg cell
   2. B
      Fusion of the nuclei of the male and female gametes
      Correct
   3. C
      Replication of chromosomes without cell division
   4. D
      Separation of homologous chromosome pairs
   Show answerHide answer

   Answer: B

   Fertilisation is the process by which the nuclei of the male gamete (sperm) and female gamete (egg) fuse to form a single diploid cell called the zygote. This fusion, also called syngamy, restores the full chromosome number (2n) from the two haploid gametes (n). The zygote then undergoes mitotic divisions to develop into an embryo. Meiosis is involved in forming the gametes, not in fertilisation itself. Chromosome replication and homologous chromosome separation are events of mitosis and meiosis respectively, occurring before and after fertilisation.

10. 10.Which of the following structures in a flower develops into the seed?
    1. A
       Ovule
       Correct
    2. B
       Style
    3. C
       Stigma
    4. D
       Ovary
    Show answerHide answer

    Answer: A

    The ovule is the structure within the ovary of a flower that, after fertilisation, develops into the seed. It contains the female gametophyte and the egg cell. When pollen fertilises the egg, the ovule transforms: the integuments become the seed coat (testa), the fertilised egg (zygote) develops into the embryo, and the endosperm provides food. The ovary wall develops into the fruit (pericarp), not the seed. The stigma and style are parts of the pistil involved in pollen reception and pollen tube growth but do not develop into seeds.

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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