WAEC Agriculture 2018
Questions & Answers

1) Distractor check: Option A (Respiration) is the exact biological opposite process involving the breakdown of compounds, which students frequently confuse with carbon dioxide intake. 2) Reasoning to the answer: Green plants utilize sunlight, water, and carbon dioxide to manufacture glucose and oxygen through photosynthesis. This mechanism successfully transforms inorganic atmospheric carbon dioxide into essential organic compounds. 3) Common mistake: Confusing plant respiration (which releases carbon dioxide) with photosynthesis (which fixes carbon dioxide into organic compounds).

1) Distractor check: Options B, C, and D are vegetative propagation methods used successfully for many other economic trees, making them seem viable for oil palms as well. 2) Reasoning to the answer: Oil palm plants are predominantly propagated through seed sowing because they are cross-pollinated and benefit greatly from genetic diversity. Vegetative cloning methods remain difficult due to major challenges with root generation. 3) Common mistake: Assuming major tropical tree crops rely primarily on vegetative techniques like grafting rather than seed sowing.

1) Distractor check: Options B, C, or D suggest deeper planting depths, which students might guess if they think deeper soil protects seeds from surface heat or predators. 2) Reasoning to the answer: Because millet seeds are very small, they require a shallow planting depth of one to three centimeters. Sowing them any deeper will deplete their limited energy reserves before emergence, resulting in poor germination rates. 3) Common mistake: Planting tiny seeds too deeply under the false assumption that deeper soil burial improves overall protection and moisture access always improve crop establishment.

Students might mistakenly choose Nitrogen, Phosphorus, or Potassium thinking of general plant macronutrients, but only Calcium serves as a key component of pectin in cell walls to provide structural integrity. Deficiencies in this nutrient lead to weak walls, blossom-end rot in fruits, and increased susceptibility to diseases. Common mistake: confusing general plant growth nutrients with specific structural wall components.

Students might mistakenly select Aeroponics, Aquaponics, or Sand culture because they involve alternative agricultural systems, but Hydroponics specifically involves growing plants in a nutrient-rich water solution without soil. It often uses inert media like gravel for mechanical support, allowing precise control over nutrients and water. Common mistake: confusing soil-less liquid culture with aerated or fish-integrated systems.

Students might mistakenly pick Fusarium wilt or Verticillium wilt because they are well-known plant diseases, or Angular leaf spot for its similar leaf symptom name, but Bacterial blight of cotton is specifically caused by Xanthomonas campestris pv. malvacearum and results in water-soaked lesions on leaves and stems, whereas the others are fungal diseases. Common mistake: failing to distinguish between bacterial pathogens and fungal wilts.

Students might mistakenly choose Soil pH, Soil color, or Soil depth thinking they dictate soil stability, but Vegetation cover is the primary factor that protects soil from raindrop impact and wind. It binds soil particles with roots and reduces erosion, while a lack of cover increases runoff and soil loss significantly. Common mistake: assuming chemical properties like pH drive physical erosion rates more than surface cover.

Students might mistakenly select Goat, Sheep, or Camel because they are also livestock kept in the region, but Cattle, particularly breeds like White Fulani and N'Dama, are the main dairy animals in West Africa. This is due to their high milk yield potential under traditional and improved systems. Common mistake: assuming all livestock species in the region serve equal primary dairy functions.

Students might mistakenly choose Thinning, Girdling, or Coppicing since they are all tree management techniques, but Pruning specifically involves selectively removing dead, diseased, or unwanted branches. This practice promotes healthy growth, improves fruit production, and enhances tree structure. Common mistake: confusing the removal of dead wood with complete stem removal or bark ringing.

Students might mistakenly select Salting, Curing, or Freezing because they are standard food preservation methods, but Smoking specifically preserves meat by drying it with smoke, which contains antimicrobial compounds and imparts flavor, reducing moisture and inhibiting bacterial growth. Common mistake: assuming all dehydration-based preservation methods involve chemical curing or freezing.

Students might mistakenly pick Culling, Crossbreeding, or Inbreeding because they are all common livestock breeding management terms, but Selection is the deliberate choice of animals with superior genetic traits (such as milk yield or growth rate) to improve the herd over generations through breeding. Common mistake: confusing the elimination of poor animals with the positive choice of breeding stock.

Students might mistakenly choose Potassium, Magnesium, or Phosphorus because they are prominent plant nutrients, but Manganese is specifically a micronutrient essential for photosynthesis and enzyme activation, whereas the others are macronutrients required in larger quantities. Common mistake: failing to differentiate between macro-elements and micro-elements based on required plant quantities.

Students might mistakenly pick Apiculture, Pisciculture, or Sericulture because they are specialized animal rearing practices, but Turkey farming specifically refers to the rearing of turkeys (Meleagris gallopavo) for meat, eggs, or feathers. This is distinct from beekeeping (apiculture), fish farming (pisciculture), or silkworm rearing (sericulture). Common mistake: confusing general poultry nomenclature with specialized non-mammalian and non-avian farming terms.

Students might mistakenly choose Leaf curling, Stunted roots, or Yellow veins because they are common symptoms of various plant disorders, but Zinc deficiency specifically causes rosette symptoms in crops like citrus and maize, featuring shortened internodes and small, clustered leaves while affecting hormone production and growth. Common mistake: attributing clustered, small leaf growth to general viral leaf curl instead of specific micronutrient shortages.

Students might mistakenly select Plowing, Burning, or Harrowing as primary land preparation tools, but Flooding and leveling create a uniform water layer essential for lowland rice. This practice controls weeds, improves nutrient availability, and facilitates transplanting or direct seeding. Common mistake: treating paddy preparation the same as dryland crop tillage.

Students might mistakenly pick Leucaena, Centrosema, or Stylosanthes because they are common forage options, but Napier grass (Pennisetum purpureum) is a non-leguminous perennial grass used for fodder, whereas the others are leguminous and capable of nitrogen fixation. Common mistake: assuming all high-yield forage crops possess nitrogen-fixing capabilities.

Students might mistakenly select Rickets, Anemia, or Scurvy because they are classic nutrient-deficiency diseases, but Vitamin A deficiency impairs vision, specifically leading to night blindness (nyctalopia) in animals by affecting rhodopsin production in the retina. Common mistake: confusing bone or blood deficiencies with retinal function disorders caused by vitamin shortages.

Students might mistakenly choose options like Increases pest attack, Reduces crop yield, or Promotes erosion assuming multiple crops create competition or damage, but Intercropping—especially with legumes—improves soil fertility through nitrogen fixation and efficient resource use, while also suppressing weeds and reducing pest pressure. Common mistake: assuming growing multiple crop species simultaneously always harms overall productivity.

Students might mistakenly select Zero grazing, Extensive system, or Intensive system because they describe overall livestock management, but Rotational grazing specifically divides pasture into paddocks, allowing controlled access to prevent overgrazing, improve forage regrowth, and enhance soil health. Common mistake: confusing enclosed confinement feeding with controlled paddock rotation.

Students might mistakenly pick Aphid, Mealybug, or Whitefly because they are major agricultural pests, but Root-knot nematodes (Meloidogyne spp.) specifically infest cassava roots, causing galls and yield loss, whereas the others primarily affect shoots or leaves. Common mistake: attributing underground root galls to surface-feeding sap-sucking insects.