WAEC Agricultural Science 1998 past questions
Ten questions from the 1998 WAEC Agricultural Science paper, with answers and explanations. We hold 50 questions from this paper, and the Skolra app has all of them.
WAEC Agricultural Science 1998 questions and answers
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1.The physiological changes that show up during disease attack on crop plants are referred to as
- ASymptomsCorrect
- BSigns
- CPathogenesis
- DSyndrome
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Answer: A
Symptoms are the correct answer. When a pathogen attacks a crop plant, it disrupts the plant's normal internal processes (water uptake, photosynthesis, translocation of nutrients, cell division), and the visible outward expression of these disturbed physiological processes — wilting, yellowing (chlorosis), stunting, rotting, leaf spots, and so on — are called symptoms. They are changes produced BY the host plant's own tissues in reaction to the disease.
- A
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2.Wastage of agricultural products during harvesting period is due mainly to inadequate
- AAgricultural education and extension services
- BStorage and processing facilitiesCorrect
- CTransport facilities
- DImplementation of government policies on agriculture
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Answer: B
After crops are harvested, they are perishable and must either be stored properly or processed quickly before they spoil, rot, or get attacked by pests, moulds and weather. Most Nigerian farmers harvest more produce than they can immediately sell or consume, so without adequate storage structures (like proper barns, silos or cribs) and processing facilities (for drying, milling, canning, etc.), a large proportion of the harvest is lost to decay before it reaches the market. This is why inadequate storage and processing facilities is the main cause of post-harvest wastage.
- A
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3.Cow dung is usually added to a fish pond in order to encourage the growth of
- APlanktonCorrect
- BHarmful bacteria
- CFish eggs
- DWeeds
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Answer: A
Plankton is correct. Cow dung is organic manure. When it is added to a fish pond, it breaks down and releases nutrients such as nitrates and phosphates into the water. These nutrients fertilize the pond and cause a rapid growth of plankton (the tiny floating plants and animals, i.e. phytoplankton and zooplankton) in the water. Plankton is the natural food of many pond fish, especially at their early stages, so more plankton means more food and better fish growth.
- A
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4.Combine harvester is usually used for harvesting
- ATuber crops such as yam and cassava
- BVegetable crops such as tomato and pepper
- CTree crops such as oil palm and cocoa
- DCereal crops such as maize, rice and wheatCorrect
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Answer: D
Cereal crops such as maize, rice and wheat are what a combine harvester is built for.
So remember: combine harvester → cereal (grain) crops.
- A
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5.Fruit formation in plants may be delayed by excessive availability of
- ANitrogenCorrect
- BCalcium
- CPotassium
- DPhosphorus
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Answer: A
Nitrogen is correct. Nitrogen is the nutrient responsible for vigorous vegetative growth — it builds leaves, stems and chlorophyll. When nitrogen is supplied in excess, the plant channels its energy into producing lush leaves and stems instead of switching over to the reproductive (flowering and fruiting) stage, so fruit formation is delayed.
So remember: too much nitrogen = too much leaf, too little fruit.
- A
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6.Gummosis is caused by a
- Anematode
- BfungusCorrect
- Cbacterium
- Dvirus
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Answer: B
Gummosis is a plant disease condition in which gum oozes out from cracks, cankers or wounds on the bark and trunk of a plant, commonly seen in citrus and other fruit trees in Nigerian orchards.
- A
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7.The source of farm credit which is interest-free is
- ACooperative societies
- BRelatives and friendsCorrect
- CMoney lenders
- DCommercial banks
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Answer: B
Farmers obtain credit from several sources, including commercial banks, specialised agricultural banks, cooperative societies, money lenders, and relatives and friends.
- A
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8.The effects of high environmental temperature on dairy cows include the following except
- AIncrease in feed intakeCorrect
- BLoss of body weight
- CIncrease in respiratory rate
- DReduction in milk yield
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Answer: A
When environmental temperature rises above a dairy cow's comfort zone, the animal goes into heat stress, and its body tries hard to lose excess heat and conserve energy. This produces a set of well-known effects.
A cow under heat stress pants and breathes faster to lose heat through evaporation from the lungs and mouth, so an increase in respiratory rate is a genuine effect, not the exception.
- A
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9.A miracidium is a larval stage of a
- Aliver flukeCorrect
- Broundworm
- Chookworm
- Dtapeworm
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Answer: A
A miracidium is the first larval stage that hatches from the egg of the liver fluke (Fasciola species), a flatworm (trematode) parasite that infects the liver and bile ducts of sheep, goats and cattle.
- A
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10.Gneiss id a metamorphic rock formed from
- ASandstone
- BGraniteCorrect
- CLimestone
- DShale
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Answer: B
Granite is correct. Gneiss is a metamorphic rock, which means it was once a different rock that got changed by intense heat and pressure deep in the earth without melting completely. The parent rock of gneiss is granite — an igneous rock. Under heat and pressure, granite's minerals re-arrange into the banded (streaky) pattern that is typical of gneiss.
So whenever you see "gneiss," think "granite that has been metamorphosed."
- A
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 50 questions we hold from the 1998 paper, on a timed CBT screen
Every question has the answer and an explanation, in the Skolra app.