WAEC Biology 2016 past questions

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

Ten questions from the 2016 WAEC Biology paper, with answers and explanations. We hold 52 questions from this paper, and the Skolra app has all of them.

WAEC Biology 2016 questions and answers

1. 1.The function of the villi in the alimentary canal is to
   1. A
      Produce digestive enzymes for protein breakdown
   2. B
      Secrete bile for emulsification of fats
   3. C
      Store glycogen for energy release during digestion
   4. D
      Increase the surface area for absorption of digested food
      Correct
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   Answer: D

   Villi are finger-like projections on the inner lining of the small intestine that enormously increase the surface area available for absorption of digested food molecules. Each villus contains a network of blood capillaries that absorb glucose and amino acids, and a central lacteal (lymph capillary) that absorbs fatty acids and glycerol. The villi are further covered with microvilli (brush border) to amplify the absorptive surface even more. This adaptation ensures that the maximum amount of nutrients from digested food is efficiently absorbed into the bloodstream.
2. 2.

   (a) (i) What is a habitat?

   (ii) Explain briefly three roles of a decomposer in an ecosystem.

   (b) Explain briefly energy flow in a freshwater habitat.

   (c) (i) State three harmful effects or microorganisms to plants

   (ii) State six beneficial effects of microorganism to humans.

   1. A
      Converting solar energy into chemical energy stored in glucose
   2. B
      Breaking down dead organic matter and recycling nutrients back into the ecosystem
      Correct
   3. C
      Consuming primary producers to transfer energy through food chains
   4. D
      Fixing atmospheric nitrogen exclusively for direct plant uptake
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   Answer: B

   Decomposers such as bacteria and fungi break down dead organic matter (dead plants, animals and their waste) into simpler inorganic substances through the process of decomposition. This returns essential nutrients such as carbon, nitrogen and phosphorus to the soil, where they can be reabsorbed by plants to continue the nutrient cycle. Without decomposers, dead material would accumulate indefinitely and nutrients would remain locked in an unusable form. Decomposers therefore play a critical role in maintaining the productivity of ecosystems.
3. 3.The cells and tissues of the nose, throat, chest, diaphragm and lungs form the
   1. A
      Excretory system
   2. B
      Respiratory system
      Correct
   3. C
      Circulatory system
   4. D
      Nervous system
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   Answer: B

   The respiratory system consists of all the structures involved in the process of breathing and gas exchange. These include the nose, nasal cavity, pharynx (throat), larynx, trachea, bronchi, bronchioles, lungs (alveoli), the diaphragm and the chest (intercostal muscles and rib cage). Together these organs work to draw air in and out of the body and facilitate the transfer of oxygen into the blood and removal of carbon dioxide. The circulatory system then transports these gases to and from body cells.
4. 4.

   (a) (i) List three forms in which living cells exist

   (ii) Give one example each of the forms listed in 1 (a)(a)

   (b) Make a diagram, 6 cm — 10 cm long, of a typical plant cell and label fully

   (c) (i) In a tabular form, state three differences between a plant cell and animal cell.

   (ii) State three similarities between a plant cell and animal cell.
   

   1. A
      Cell wall
      Correct
   2. B
      Nucleus
   3. C
      Mitochondria
   4. D
      Cell membrane
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   Answer: A

   The cell wall is a rigid structure composed mainly of cellulose that surrounds the cell membrane in plant cells. It provides structural support and prevents the cell from bursting when turgid. Animal cells lack a cell wall entirely, which is why they are more flexible in shape. Both plant and animal cells possess a cell membrane, nucleus and mitochondria as common features. Other plant-specific structures include the chloroplast and a large central vacuole.
5. 5.The association between two organisms in which one of the organisms gains and the other loses is referred to as
   1. A
      Commensalism
   2. B
      Parasitism
      Correct
   3. C
      Symbiosis
   4. D
      Mutualism
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   Answer: B

   Parasitism is an association in which one organism (the parasite) benefits by obtaining food, shelter or other needs from another organism (the host), which is harmed in the process. Examples include tapeworms in the intestine of mammals and Plasmodium in human red blood cells. Mutualism benefits both organisms, commensalism benefits one without harming the other, and symbiosis is a broad term covering all close associations. The key characteristic of parasitism is the +/− relationship — one gains, one loses.
6. 6.A noticeable physical appearance of individuals of the same species is called
   1. A
      Phenotype
      Correct
   2. B
      Genotype
   3. C
      Chromosome
   4. D
      Allele
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   Answer: A

   Phenotype refers to the observable physical, biochemical or behavioural characteristics of an organism, resulting from the interaction of its genotype with the environment. Examples include coat colour, flower colour, height and blood group. The genotype is the genetic make-up (allele combination) of an organism, which may not always be directly visible. An allele is a variant form of a gene, and a chromosome is a structure made of DNA that carries genes. The phenotype is what can be directly observed or measured in a living organism.
7. 7.Food webs are complex because
   1. A
      Energy flows in only one fixed direction throughout all ecosystems
   2. B
      Many organisms feed on more than one type of food
      Correct
   3. C
      All organisms in a food web belong to a single trophic level
   4. D
      All organisms in a habitat feed exclusively on a single food source
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   Answer: B

   A food web is complex because most organisms are omnivores or have varied diets, meaning they consume more than one type of prey or food source. This creates multiple intersecting and overlapping food chains rather than a single linear chain. For example, a frog may eat insects, worms and spiders, each of which is itself part of a different food chain. The resulting network of feeding relationships is the food web. This complexity provides ecological stability — if one food source becomes scarce, organisms can switch to alternative prey, reducing the risk of population collapse.
8. 8.In which of the plant tissues are guard cells located?
   1. A
      Xylem
   2. B
      Mesophyll
   3. C
      Phloem
   4. D
      Epidermis
      Correct
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   Answer: D

   Guard cells are specialised cells found in the epidermis (the outermost layer) of leaves and stems. They occur in pairs and surround a pore called the stoma. Guard cells contain chloroplasts and regulate the opening and closing of stomata by changing their turgidity in response to light, CO₂ concentration and water availability. When guard cells are turgid the stomata open, allowing gas exchange and transpiration; when flaccid, the stomata close. The mesophyll is where photosynthesis occurs, while xylem and phloem are vascular tissues.
9. 9.Scientists who study genetics are known as
   1. A
      Microbiologists
   2. B
      Ecologists
   3. C
      Geneticists
      Correct
   4. D
      Taxonomists
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   Answer: C

   Geneticists are scientists who specialise in the study of genetics — the science of heredity and variation in living organisms. Their work covers areas such as gene structure and function, inheritance patterns, mutation, genetic engineering and genomics. Taxonomists classify and name organisms, ecologists study relationships between organisms and their environments, and microbiologists study microscopic organisms. Genetics as a formal discipline began with Gregor Mendel in the 19th century and has grown to encompass molecular biology and biotechnology.
10. 10.Which of the following actions supports conservation? To
    1. A
       Allow industrial effluents to flow into rivers
    2. B
       Plant trees to replace those that have been felled
       Correct
    3. C
       Clear forests for agricultural purposes
    4. D
       Hunt wild animals for sport and recreation
    Show answerHide answer

    Answer: B

    Planting trees to replace felled ones (reforestation) is a direct act of conservation because it restores vegetation, maintains biodiversity, prevents soil erosion and sustains the carbon cycle. Clearing forests for farming (deforestation), discharging industrial effluents (water pollution) and hunting wild animals all deplete natural resources and damage ecosystems, which are the opposite of conservation. Conservation requires the sustainable management of resources so that they remain available for current and future generations without causing lasting harm to the environment.

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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