WAEC Agricultural Science 2023 past questions

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

Ten questions from the 2023 WAEC Agricultural Science paper, with answers and explanations. We hold 37 questions from this paper, and the Skolra app has all of them.

WAEC Agricultural Science 2023 questions and answers

1. 1.The bacterium which is responsible for conversion of ammonium compounds to nitrites in the nitrogen cycle is
   1. A
      Nitrosomonas
      Correct
   2. B
      Pseudomonas
   3. C
      Rhizobium
   4. D
      Nitrobacter
   Show answerHide answer

   Answer: A

   The nitrogen cycle's nitrification stage happens in two steps, each carried out by a different bacterium:

   Step 1: Ammonium compounds (NH₄⁺) in the soil are oxidised to nitrites (NO₂⁻) by Nitrosomonas.
   Step 2: Those nitrites are then oxidised further to nitrates (NO₃⁻) — the form plants actually absorb — by Nitrobacter.

2. 2.Maceration is carried out in the processing of
   1. A
      Cocoa
   2. B
      Paddy rice
   3. C
      Cotton
   4. D
      Oil palm
      Correct
   Show answerHide answer

   Answer: D

   Maceration means softening tissue by soaking or digesting it so that cells break down and release their contents. In farm produce processing, this is the digestion stage of oil palm processing: after the harvested bunches are sterilized and the fruits stripped off, the fruits are macerated (digested) in a digester, usually with heat, to soften and break down the fibrous mesocarp. This frees the palm oil trapped in the pulp so it can be pressed out in the next stage.

   So the correct answer is oil palm, since maceration (digestion) is specifically the step that breaks down the fruit pulp before oil extraction.

3. 3.A major reason for encouraging afforestation in arid regions of West Africa is to
   1. A
      increase the amount of rainfall in the region
   2. B
      provide timber for construction works
   3. C
      provide pasture for grazing livestock
   4. D
      check desert encroachment
      Correct
   Show answerHide answer

   Answer: D

   Afforestation means deliberately planting trees in an area that previously had none. In the arid and semi-arid belt of West Africa (the Sahel zone, including northern Nigeria, Niger, and Chad), the major reason for this is to check desert encroachment — tree roots bind the loose, sandy soil together, and the planted belts act as windbreaks that slow down wind erosion and stop the desert from advancing further south. This is why programmes such as the "Green Wall" shelterbelt schemes exist along this zone.

4. 4.The part of a disc plough to which discs are connected is
   1. A
      Standard
   2. B
      Scraper
   3. C
      Disc axle (gang bolt)
      Correct
   4. D
      Furrow wheel
   Show answerHide answer

   Answer: C

   In a disc plough, the concave discs are not bolted straight onto the frame. They are threaded, one after another with a spool (spacer) between each pair, onto a long steel shaft called the disc axle, also known as the gang bolt or arbor bolt. This bolt passes right through the centre hole of every disc and clamps them tightly together so the whole set of discs turns as one unit when the plough is pulled through the soil.

5. 5.A pest of honeybee is
   1. A
      Wax moth
      Correct
   2. B
      Cotton stainer
   3. C
      Weevil
   4. D
      Tsetse fly
   Show answerHide answer

   Answer: A

   The wax moth (Galleria mellonella) is a well-known pest of honeybee colonies. Its larvae burrow into the comb, feeding on beeswax, pollen and cocoon silk, which destroys the comb structure and weakens or drives away the colony. This is why beekeepers in apiculture practice must regularly inspect hives and keep colonies strong to prevent wax moth infestation.

6. 6.Which of the following crops require a nursery?
   1. A
      Cowpea
   2. B
      Cassava
   3. C
      Tomato
      Correct
   4. D
      Maize
   Show answerHide answer

   Answer: C

   Tomato is the crop that requires a nursery. Its seeds are very tiny and the young seedlings are delicate, so farmers raise them in a nursery bed (or seed tray) for about 4–6 weeks, where watering, shade, and protection from pests and harsh weather can be closely controlled. Only the strong, healthy seedlings are then transplanted to the main field, which gives a more uniform stand and saves land and water during the early growth stage.

7. 7.The risk of production in agricultural business is borne by the
   1. A
      Financier (creditor)
   2. B
      Labourer
   3. C
      Landowner
   4. D
      Entrepreneur (farm manager)
      Correct
   Show answerHide answer

   Answer: D

   In agricultural business, there are four factors of production, and each one earns a specific type of reward: land earns rent, labour earns wages, and capital earns interest. These three payments are fixed and contractual — they must be paid whether the farm business makes a profit or a loss.

8. 8.Grading of farm produce is important because it
   1. A
      it reduces the overall cost of producing the crop or livestock
   2. B
      it prevents the produce from spoiling while in storage
   3. C
      it sorts produce into quality classes, which ensures fair pricing and better marketability
      Correct
   4. D
      it increases the total quantity of produce harvested from the farm
   Show answerHide answer

   Answer: C

   Grading is the sorting of farm produce into different classes or standards based on qualities such as size, weight, colour, maturity, freedom from defects, and so on.

   So the correct reasoning is that grading is important because it sorts produce into quality classes, which ensures fair pricing and better marketability.

9. 9.Monocotyledonous crops are characterized by
   1. A
      Net-veined (reticulate) leaves
   2. B
      Two cotyledons in the seed
   3. C
      A taproot system with well-developed lateral roots
   4. D
      A fibrous root system
      Correct
   Show answerHide answer

   Answer: D

   Monocotyledonous crops (e.g. maize, rice, guinea corn, sugarcane, onion) are a distinct group of flowering plants with seeds that have one cotyledon (seed leaf). This single-cotyledon seed structure is linked to a set of other features that go together as a package: parallel leaf venation, scattered vascular bundles in the stem, and most importantly for this question, a fibrous root system — many thin roots of similar size spreading out from the base of the stem, with no single dominant root.

10. 10.Seedlings are best transplanted in the field
    1. A
       at any time of the day, once the nursery seedlings have matured
    2. B
       in the heat of the afternoon, so the warm soil can speed up rooting
    3. C
       at midday, under full sunshine, to expose the seedlings to maximum light
    4. D
       in the early morning or late evening, when the weather is cool and transpiration is low
       Correct
    Show answerHide answer

    Answer: D

    When a seedling is uprooted from the nursery, its roots are damaged and cannot yet absorb water fast enough to replace what the leaves lose through transpiration. If transplanting is done under hot, sunny conditions, the seedling loses water faster than its injured roots can take it up, and it wilts or dies — this is called transplanting shock.

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 37 questions we hold from the 2023 paper, on a timed CBT screen

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