WAEC Agricultural Science 2008 past questions

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

Ten questions from the 2008 WAEC Agricultural Science paper, with answers and explanations. We hold 56 questions from this paper, and the Skolra app has all of them.

WAEC Agricultural Science 2008 questions and answers

1. 1.sources of nitrogen to the soil include the following except
   1. A
      Nitrogen fixation by leguminous plants
   2. B
      Decomposition of organic matter by soil microorganisms
   3. C
      Leaching of nitrates from the topsoil
      Correct
   4. D
      Electrical fixation of atmospheric nitrogen by lightning
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   Answer: C

   Correct answer: Leaching of nitrates from the topsoil.

   The soil gains nitrogen from several natural and man-made processes: decomposition of organic matter (dead plants, animals and manure are broken down by soil microorganisms, releasing nitrogen compounds); nitrogen fixation by leguminous plants (Rhizobium bacteria living in the root nodules of legumes like beans and groundnut convert atmospheric nitrogen into a form plants can use); and electrical fixation by lightning (lightning supplies the energy needed to combine atmospheric nitrogen with oxygen, and the resulting compounds are washed into the soil by rain). All three of these add nitrogen to the soil.

2. 2.Excessive drainage of soil water can be checked by the addition of adequate quantities of
   1. A
      Lime
   2. B
      Coarse sand
   3. C
      Organic matter
      Correct
   4. D
      Inorganic fertilizer
   Show answerHide answer

   Answer: C

   Organic matter is correct. Excessive drainage happens in soils with large pore spaces (typically sandy soils), where water moves through too quickly for plant roots to absorb it. Adding adequate quantities of organic matter (compost, farmyard manure, crop residues) improves the soil's water-holding capacity because humus particles are colloidal and retain moisture, while also improving soil structure and reducing the rate at which water percolates away.

3. 3.The term supplying in crop production means
   1. A
      Spacing out crops during planting
   2. B
      Pruning excess branches of crops
   3. C
      Replacing ungerminated seeds on seedbeds
      Correct
   4. D
      Adding enough fertilizer to the crops
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   Answer: C

   Supplying is a cultural practice carried out soon after planting, when the farmer walks through the field and checks which sown spots have failed to germinate. Those gaps are then re-sown with fresh, viable seeds so that the field ends up with a full, even plant population. This is exactly what replacing ungerminated seeds on seedbeds describes, so it is the correct meaning of the term.

4. 4.swollen shoot disease of cocoa is caused by
   1. A
      fungus
   2. B
      bacteria
   3. C
      nematode
   4. D
      virus
      Correct
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   Answer: D

   Swollen shoot disease of cocoa is caused by a virus — the Cacao Swollen Shoot Virus (CSSV).

   Because the specific causal agent of swollen shoot disease is a virus transmitted by mealybugs, virus is the correct answer.

5. 5.The benefits of establishing forests do not include
   1. A
      Control of soil erosion
   2. B
      Moderation of local climate
   3. C
      Promotion of desert encroachment
      Correct
   4. D
      Provision of timber and wood products
   Show answerHide answer

   Answer: C

   Forests are established for good reasons, and checking desertification is one of them — not causing it.

   Establishing forests brings many benefits to the environment and the economy:

   • The roots of trees bind the soil together, so forests give strong control of soil erosion.
   • Trees are harvested for wood, giving timber and wood products used for building, furniture and fuel.
   • Large stands of trees release moisture through transpiration and act as windbreaks, giving moderation of local climate and rainfall patterns.
6. 6.Which of the following is not a government agricultural programme?
   1. A
      National Accelerated Food Production Programme
   2. B
      National Youth Service Corps
      Correct
   3. C
      Operation Feed the Nation
   4. D
      River Basin Development Authority
   Show answerHide answer

   Answer: B

   National Youth Service Corps (NYSC) is the correct answer because it is not a government agricultural programme. NYSC is a scheme set up to mobilise Nigerian graduates for a one-year national service in fields such as education, health, administration and community development — agriculture plays no special role in it.

7. 7.The main reason for removing the barks of cassava tubers before processing the tuber is to
   1. A
      reduce the bulkiness of the tuber for easy transportation
   2. B
      hasten the fermentation of the tuber
   3. C
      reduce the hydrocyanic (cyanide) acid content of the tuber
      Correct
   4. D
      improve the colour of the processed product
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   Answer: C

   Cassava tubers contain cyanogenic glucosides (linamarin and lotaustralin), which break down to release poisonous hydrocyanic (prussic) acid. This acid is concentrated mostly in the outer skin (bark) and the layer of flesh just beneath it.

8. 8.The three most important physical factors that influence rock weathering are
   1. A
      Rainfall, organisms and parent rock
   2. B
      Temperature, rainfall and wind
      Correct
   3. C
      Temperature, pressure and topography
   4. D
      Parent rock, organisms and time
   Show answerHide answer

   Answer: B

   Correct answer: Temperature, rainfall and wind.

   These are the three main physical (mechanical) agents of rock weathering taught in agricultural science. Temperature changes cause rocks to expand by day and contract by night; repeated over time, this cracks and breaks the rock. Rainfall hits rock surfaces and flowing water carries rock particles that knock against one another, wearing them down. Wind carries sand and rock particles that strike exposed rock surfaces, grinding them into smaller fragments. Together, these three are the physical factors emphasised in the Nigerian syllabus, since Nigeria's tropical climate makes frost/ice action largely irrelevant.

9. 9.Fertile eggs will be produced by breeders if the
   1. A
      eggs are stored at room temperature before incubation
   2. B
      hens are given a vitamin-rich supplementary feed
   3. C
      laying house is well ventilated and properly lit
   4. D
      cocks are kept together with the hens in the correct ratio
      Correct
   Show answerHide answer

   Answer: D

   Fertile eggs will be produced by breeders if the cocks are kept together with the hens in the correct ratio.

10. 10.When birds are fed on a ratio deficient in riboflavin,which of the following symptoms will they show?
    1. A
       Night blindness
    2. B
       Poor feathering
    3. C
       Rickets
    4. D
       Curled-toe paralysis
       Correct
    Show answerHide answer

    Answer: D

    Riboflavin (Vitamin B2) is needed for normal nerve and muscle function in birds. When a ration is deficient in riboflavin, chicks develop a well-known nerve disorder called curled-toe paralysis — the toes curl inward, the bird walks on its hocks with its legs weak and splayed, and in severe cases it is unable to stand at all.

    So the correct symptom of riboflavin deficiency in birds is curled-toe paralysis.

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 56 questions we hold from the 2008 paper, on a timed CBT screen

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

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