JAMB Biology 2025 past questions
Ten questions from the 2025 JAMB Biology paper, with answers and explanations. We hold 91 questions from this paper, and the Skolra app has all of them.
JAMB Biology 2025 questions and answers
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1.
Example of animal exhibiting mating colouration is
- ACichlid fishCorrect
- BGrasshopper
- CWeaver bird
- DChameleon
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Answer: A
Mating colouration is a type of adaptive colouration in which an animal develops bright, conspicuous colours mainly during the breeding season, in order to attract a mate. This is different from protective (camouflage) colouration and warning colouration.
- A
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2.
The following are factors that affect the population growth of an organism except
- AMortality
- BMutationCorrect
- CMigration
- DNatality
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Answer: B
Population growth is governed by four measurable processes: natality (birth rate, which adds individuals), mortality (death rate, which removes individuals), and migration (immigration adds individuals, emigration removes them). These directly change the number of organisms in a population over time.
- A
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3.
Agglutination occurs in blood transfusion when the
- Awhite blood cells of the donor attack the red blood cells of the recipient
- Bantibodies in the recipient's plasma react with antigens on the donor's red blood cellsCorrect
- Cantigens in the recipient's plasma react with antibodies on the donor's red blood cells
- Dplatelets in the donor's blood react with fibrinogen in the recipient's plasma
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Answer: B
Agglutination is the clumping together of red blood cells that happens during a mismatched blood transfusion.
- A
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4.
In a cross involving a heterozygous red flower plant (Rr) and a white flowered plant (rr), what is the probability that the offspring will be Rr?
- A1/4
- B1/2Correct
- C3/4
- D1/1
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Answer: B
This is a monohybrid test cross: Rr (heterozygous red) × rr (white).
Rr produces gametes R and r in equal numbers, while rr produces only r gametes. Combining them gives offspring genotypes:
R + r → Rr
r + r → rr
R + r → Rr
r + r → rrSo the offspring ratio is 2 Rr : 2 rr, which simplifies to 1 Rr : 1 rr. This means the probability that any given offspring is Rr is 1/2, correct.
- A
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5.
The cell component that stores waste products is the
- AVacuoleCorrect
- BNucleus
- CGolgi apparatus
- DLysosome
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Answer: A
The vacuole is correct. In plant cells especially, the large central vacuole is the storage sac of the cell — it holds water, mineral salts, sugars, and importantly, waste products that the cell cannot immediately get rid of, keeping them isolated from the rest of the cytoplasm so they do not interfere with metabolic reactions.
- A
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6.
Which of the following processes takes place in the carbon cycle?
- ADenitrification
- BNitrification
- CPhotosynthesisCorrect
- DAmmonification
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Answer: C
Photosynthesis is correct. In the carbon cycle, green plants and other photosynthetic organisms absorb carbon(IV) oxide (CO2) from the atmosphere and fix it into organic compounds such as glucose, using sunlight energy. This carbon then passes through food chains, is released back by respiration, decomposition, and combustion, and the cycle continues. Photosynthesis is therefore one of the defining processes of the carbon cycle.
- A
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7.
The type of germination in which the cotyledons remain below the soil surface is
- AHypogeal germinationCorrect
- BEpigeal germination
- CViviparous germination
- DCryptogeal germination
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Answer: A
Hypogeal germination is correct. In this type of germination, the hypocotyl does not elongate, so the cotyledons stay below the soil surface while only the plumule pushes upward. Examples include maize, mango, pea and broad bean.
- A
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8.
The mouth parts of a grasshopper are adapted for
- ASiphoning
- BPiercing and sucking
- CSponging
- DBiting and chewingCorrect
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Answer: D
A grasshopper is a plant-eating insect that feeds on solid leaves and grasses, so its mouthparts must be able to cut and grind tough plant tissue. It has strong, toothed mandibles for biting off pieces of leaf, together with maxillae and a labium that hold and manipulate the food while it is chewed. This arrangement is the typical mandibulate (chewing) mouthpart type, so the mouth parts of a grasshopper are adapted for biting and chewing.
- A
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9.
A structure associated with an open circulatory system is
- AHaemocoelCorrect
- BA double-walled heart with four chambers
- CValves located in veins
- DCapillaries connecting arteries to veins
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Answer: A
The haemocoel is correct. In animals with an open circulatory system, such as insects and most molluscs, blood (haemolymph) is pumped by the heart into large open body spaces called the haemocoel, where it bathes the tissues directly before draining back into the heart through small valved openings called ostia.
- A
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10.
The two - hoofed toes of camels allow easy walking on desert because of
- Aa broad, tough connecting pad that gives the foot a large surface area, spreading body weight so it does not sink into soft sandCorrect
- Bsharp claws that dig into the sand for a firm grip while walking
- Ca web-like membrane joining the toes that reduces friction as the foot moves over sand
- Da thick layer of fat under the sole that insulates the foot from the hot desert sand
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Answer: A
A camel's foot has two toes joined underneath by a broad, tough, cushion-like pad. This pad greatly increases the surface area of the foot that touches the ground.
- 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
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