JAMB Biology 2020 past questions

Checked by the Skolra question team · Last updated 23 October 2026

Ten questions from the 2020 JAMB Biology paper, with answers and explanations. We hold 35 questions from this paper, and the Skolra app has all of them.

JAMB Biology 2020 questions and answers

1. 1.

   The function of ribosome in cells is

   1. A
      synthesis of lipids
   2. B
      synthesis of proteins
      Correct
   3. C
      trapping of light energy for photosynthesis
   4. D
      release of energy through respiration
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   Answer: B

   Ribosomes are tiny organelles, found free in the cytoplasm or attached to the rough endoplasmic reticulum, whose job is to read the code carried by messenger RNA (mRNA) and link amino acids together into polypeptide chains. This process is called translation, and it is why ribosomes are described as the site of protein synthesis.

   So whenever you see a question pointing at ribosomes, always link it straight to protein synthesis.

2. 2.

   A group of organism of different species living in a particular area is described as a

   1. A
      Community
      Correct
   2. B
      Population
   3. C
      Habitat
   4. D
      Ecosystem
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   Answer: A

   Community is correct. In ecology, when organisms of different species live together in the same area and interact with one another, that collection is called a community.

   Students often confuse this with population, but a population is strictly organisms of the same species in an area (e.g. all the tilapia in a pond) — the question specifically says "different species," which rules population out.

3. 3.

   In which of the following vertebrates does the skin function as a respiratory surface

   1. A
      Fishes
   2. B
      Amphibians
      Correct
   3. C
      Reptiles
   4. D
      Birds
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   Answer: B

   Amphibians (such as the frog and toad) are the vertebrates in which the skin functions as a respiratory surface. Amphibian skin is thin, always kept moist by mucus glands, and richly supplied with blood capillaries, allowing gases to diffuse directly across it. This process, called cutaneous respiration, works alongside the lungs and buccal cavity, and it is especially important when the amphibian is in water or hibernating in mud, when the lungs are used less.

4. 4.

   What is the term used to describe biotic and abiotic factors in the environment of the organism?

   1. A
      Habitat
   2. B
      Ecological factors
      Correct
   3. C
      Biosphere
   4. D
      Ecosystem
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   Answer: B

   The living things (biotic factors) and non-living things (abiotic factors) that make up an organism's surroundings are together called the ecological factors of that environment.

5. 5.

   In an agricultural ecosystem, the biotic component consists of

   1. A
      Humidity, wind, drainage and topography of the land
   2. B
      Soil, temperature, rainfall and sunlight intensity
   3. C
      Crops, livestock, weeds, pests and micro-organisms
      Correct
   4. D
      Farm tools, fertilizers and pesticides applied by the farmer
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   Answer: C

   An ecosystem has two kinds of components: biotic (the living things) and abiotic (the non-living, physical factors). In an agricultural ecosystem, the biotic component is made up of all the living organisms present — the crops planted by the farmer, the livestock reared, the weeds that compete with the crops, the pests and insects that attack them, and the micro-organisms (bacteria and fungi) in the soil that break down organic matter.

6. 6.

   For growth to occur in organisms, the rate of

   1. A
      metabolism must be equal to that of excretion
   2. B
      catabolism must be greater than that of anabolism
   3. C
      respiration must be greater than that of photosynthesis
   4. D
      anabolism must be greater than that of catabolism
      Correct
   Show answerHide answer

   Answer: D

   Growth means a real, lasting increase in the amount of living material (cytoplasm, tissues, cells) in an organism. This is built up by anabolism — the constructive (building-up) part of metabolism, such as making proteins from amino acids or building new cell structures.

7. 7.

   The hypha of rhizopus is said to be non-septate because it

   1. A
      contains many nuclei in a continuous cytoplasm without cross walls dividing it into cells
      Correct
   2. B
      lacks a nucleus and depends entirely on the host cell for genetic material
   3. C
      is divided into distinct uninucleate cells by cross walls along its length
   4. D
      contains only one nucleus enclosed within a rigid cellulose wall
   Show answerHide answer

   Answer: A

   A hypha is described as non-septate (coenocytic) when it contains many nuclei scattered in one continuous mass of cytoplasm, with no cross walls (septa) marking it off into separate cells. This is exactly the case in Rhizopus, the common bread mould studied under Kingdom Fungi.

   So the correct reasoning is that the non-septate nature comes from the many nuclei sharing one undivided cytoplasm.

8. 8.

   Which of the following vertebrates has the most simple structured heart

   1. A
      Fish
      Correct
   2. B
      Amphibian
   3. C
      Reptile
   4. D
      Mammal
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   Answer: A

   Vertebrate hearts increase in structural complexity as you move from fish to mammals.

   Since the question asks for the vertebrate with the most simple (least complex) heart structure, the correct answer is the fish, with its plain two-chambered heart. The amphibian, reptile and mammal hearts are progressively more complex, not simpler.

9. 9.

   In a population of living things, the parameters of size, height, weight and colours are examples of

   1. A
      Adaptation
   2. B
      Natural selection
   3. C
      Mutation
   4. D
      Variation
      Correct
   Show answerHide answer

   Answer: D

   Variation is correct. Within any population of living things, individuals differ from one another in measurable and observable features such as size, height, weight and colour. These differences among members of the same species make up what biology calls variation, and traits like height and weight, which can be measured on a continuous scale, are classic textbook examples of it.

10. 10.

    Which of the following instruments is NOT used in measuring abiotic factors in any habitat?

    1. A
       Thermometer
    2. B
       Rain gauge
    3. C
       Quadrat
       Correct
    4. D
       Anemometer
    Show answerHide answer

    Answer: C

    Abiotic factors are the non-living components of a habitat, such as temperature, rainfall, wind speed, light and humidity. Each of these has a dedicated instrument for measuring it.

    The rain gauge measures rainfall, the anemometer measures wind speed, and the thermometer measures temperature — all abiotic factors. These three are correctly paired with abiotic measurement.

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

Spotted a wrong answer? Tell us from the app or on the contact page and we check it.

Practise all 35 questions we hold from the 2020 paper, on a timed CBT screen

Every question has the answer and an explanation, in the Skolra app.

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