WAEC Agricultural Science 2013 past questions

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

Ten questions from the 2013 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 2013 questions and answers

1. 1.One of the main disadvantages of mechanical tillage is the
   1. A
      it requires high cost for the purchase and maintenance of the machines
      Correct
   2. B
      it allows large areas of land to be cultivated within a short time
   3. C
      it saves a lot of time during land preparation
   4. D
      it reduces the drudgery involved in land preparation
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   Answer: A

   The stem is completed correctly by: "...the high cost of purchase and maintenance of the machines."

2. 2.Some plants are suitable for decorating living rooms because of their
   1. A
      aesthetic value
      Correct
   2. B
      medicinal value
   3. C
      economic value
   4. D
      nutritive value
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   Answer: A

   Plants chosen to decorate living rooms (ornamental or indoor plants) are selected mainly for their aesthetic value — that is, their attractive leaves, flowers, colour, shape or general appearance, which beautify the home.

3. 3.Which of the following factors affects the onset of flowering in crops?
   1. A
      Soil texture
   2. B
      Plant population (spacing)
   3. C
      Photoperiod (length of daylight)
      Correct
   4. D
      Method of harvesting
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   Answer: C

   Photoperiod (the length of daylight a plant receives) is correct. Flowering in many crops is triggered by day length, a response called photoperiodism. Short-day crops (e.g. rice, maize, cotton) flower when day length falls below a critical value, while long-day crops flower when day length exceeds a critical value. This is why some crops only flower at certain times of the year in response to changing day length, making it one of the major environmental factors controlling the onset of flowering.

4. 4.Which of the following sequences describes the steps in making hay?
   1. A
      Cutting → Drying → Baling → Storing
      Correct
   2. B
      Cutting → Baling → Drying → Storing
   3. C
      Cutting → Drying → Storing → Baling
   4. D
      Drying → Cutting → Baling → Storing
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   Answer: A

   Cutting → Drying → Baling → Storing is the correct order of operations in making hay.

5. 5.Heat in farm animals can be detected by the following signs except
   1. A
      Restlessness and frequent bellowing
   2. B
      Mounting of other animals
   3. C
      Swelling and reddening of the vulva
   4. D
      Noticeable loss of body weight
      Correct
   Show answerHide answer

   Answer: D

   Heat (oestrus) is the period when a female farm animal is receptive to mating and shows clear behavioural and physical changes. A farmer or attendant recognises heat from these signs:

   Restlessness and frequent bellowing — the animal becomes agitated, moves about more, and vocalises more than usual.

   Noticeable loss of body weight is not a recognised sign of heat. Heat is a short reproductive event (lasting roughly a day in most farm animals) and does not cause weight loss; weight loss instead points to poor nutrition, parasites or disease, not oestrus. This is the odd one out, so it is the correct answer to "except".

6. 6.A disease of rabbit caused by a protozoan is
   1. A
      Mange
   2. B
      Pasteurellosis
   3. C
      Myxomatosis
   4. D
      Coccidiosis
      Correct
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   Answer: D

   Coccidiosis is the disease of rabbits caused by a protozoan. It is caused by tiny single-celled protozoan parasites of the genus Eimeria, which attack the liver and intestinal lining of the rabbit, causing diarrhoea, poor growth, and sometimes death in young rabbits.

   Since only coccidiosis among these four is caused by a protozoan, it is the correct answer.

7. 7.A farmer who plants African Marigold between his crops has the intention of controlling
   1. A
      weeds
   2. B
      fungal diseases
   3. C
      rodents
   4. D
      nematodes
      Correct
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   Answer: D

   African Marigold (Tagetes erecta) is a well-known companion plant used in intercropping specifically because its roots release a chemical called alpha-terthienyl into the soil. This substance is toxic to soil-borne pests and inhibits the hatching of their eggs.

8. 8.If rows are spaced 1.0m apart with one plant per stand, determine the spacing between stands in order to obtain a plant population of 40,000/ha
   1. A
      0.40 m
   2. B
      0.50 m
   3. C
      0.25 m
      Correct
   4. D
      2.50 m
   Show answerHide answer

   Answer: C

   Working: Plant population is found from the formula:

   Population (plants/ha) = 10,000 m² (area of 1 hectare) ÷ (row spacing × spacing between stands)

   We are told row spacing = 1.0 m and the target population = 40,000 plants/ha. Substituting:

   40,000 = 10,000 ÷ (1.0 × spacing between stands)

   So spacing between stands = 10,000 ÷ 40,000 = 0.25 m.

9. 9.Which of the following species of bacteria lives symbiotically in root nodules of legumes?
   1. A
      Nitrosomonas
   2. B
      Rhizobium
      Correct
   3. C
      Nitrobacter
   4. D
      Azotobacter
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   Answer: B

   Rhizobium is the bacterium that lives symbiotically in the root nodules of legumes (beans, cowpea, groundnut, soyabean). It infects the root hairs of the legume, forming swellings (nodules), and fixes atmospheric nitrogen into a form the plant can use, while the plant in turn supplies the bacterium with carbohydrates. This mutual benefit is what makes the relationship symbiotic.

   So whenever a question links nitrogen-fixing bacteria specifically to root nodules of legumes, the correct answer is always Rhizobium.

10. 10.To facilitate mechanical harvesting of cereals, it is better to
    1. A
       practice mixed cropping with other crops
    2. B
       broadcast the seeds across the field
    3. C
       plant the crop in straight rows
       Correct
    4. D
       plant the crop on mounds
    Show answerHide answer

    Answer: C

    Planting the crop in straight rows is the correct practice. A combine harvester (or any mechanical harvester) moves forward in a straight line with a fixed cutting bar at the front. It can only do its job cleanly when the cereal plants (maize, rice, sorghum, wheat, etc.) stand in evenly spaced, straight rows that match the width of the machine's header, so every plant is cut and fed into the machine in one pass.

    So, to make mechanical harvesting of cereals efficient, the crop must be planted in straight, evenly spaced rows.

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 2013 paper, on a timed CBT screen

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