JAMB Biology 2016 past questions
Ten questions from the 2016 JAMB Biology paper, with answers and explanations. We hold 50 questions from this paper, and the Skolra app has all of them.
JAMB Biology 2016 questions and answers
-
1.If the cross of a red-flowered plant with a white flowered plant produces a pink flowered plant, this is an example of
- AIncomplete dominanceCorrect
- BLinkage
- CSegregation
- DCodominance
Show answerHide answer
Answer: A
This is incomplete dominance: neither the red allele nor the white allele is fully dominant over the other, so the heterozygous offspring shows a blended, in-between phenotype — pink.
- A
-
2.Which of the following can cause shrinkage of living cells?
- ADistilled water
- BHypertonic solutionCorrect
- CIsotonic solution
- DHypotonic solution
Show answerHide answer
Answer: B
Placing a living cell in a hypertonic solution (one with a higher solute concentration than the cell's cytoplasm) causes water to leave the cell by osmosis, making it shrink — in plant cells this is seen as plasmolysis.
A hypotonic solution or distilled water would instead make water enter the cell (swelling it), and an isotonic solution causes no net change in size.
- A
-
3.The relationship between a termite and the protozoam in its intestine is described as
- AMutualismCorrect
- BCommensalism
- CParasitism
- DPredation
Show answerHide answer
Answer: A
This is mutualism: the termite's gut protozoa digest cellulose in the wood the termite eats (which the termite's own enzymes cannot break down), releasing nutrients the termite can absorb; in return the protozoa get a safe habitat and a steady food supply.
- A
-
4.Which of the following protects the essential parts of the flower at bud stage?
- ACorolla
- BAndroecium
- CGynoecium
- DCalyxCorrect
Show answerHide answer
Answer: D
The calyx (the ring of sepals) is the outermost and usually toughest part of the flower. While the flower is still in bud, the calyx wraps around and protects the delicate corolla, stamens and carpels inside.
- A
-
5.An example of a non-bio degrable pollutants is
- APlasticCorrect
- BDead leaves
- CSewage
- DPaper
Show answerHide answer
Answer: A
Plastic is a classic non-biodegradable pollutant — it is not broken down by decomposer organisms and can persist in the environment for hundreds of years.
Paper, dead leaves and sewage are all organic materials that decomposers (bacteria and fungi) can break down naturally over a relatively short time, making them biodegradable.
- A
-
6.The theory of use and disuse of organs was promulgated by
- AHugo de Vries
- BCharles Darwin
- CJean-Baptiste LamarckCorrect
- DGregor Mendel
Show answerHide answer
Answer: C
Jean-Baptiste Lamarck proposed the theory of use and disuse of organs: body parts used frequently become stronger and more developed, while unused parts weaken and shrink, and he believed these changes could be inherited by offspring.
- A
-
7.
When a cell is placed in solution and the size of the cell increases, the concentration of solution is said to be
- AIsotonic
- BHypertonic
- CHypotonicCorrect
- DSaturated
Show answerHide answer
Answer: C
When a cell is placed in a hypotonic solution, the solution has a lower solute concentration (higher water concentration) than the cell's contents, so water moves into the cell by osmosis, making it swell.
A hypertonic solution would draw water OUT of the cell, causing it to shrink, and an isotonic solution has no net water movement, so the cell's size stays the same.
- A
-
8.When sickle cell carrier marries a normal woman, the probability of them having a normal offspring is
- A1
- B1/4
- C3/4
- D1/2Correct
Show answerHide answer
Answer: D
Genotype AS (sickle-cell carrier) crossed with AA (normal): the Punnett square gives offspring genotypes AA, AA, AS, AS in equal numbers — that is, half (1/2) are normal (AA) and half are carriers (AS). No child in this cross can be SS.
- A
-
9.In the nitrogen cycle, the nitrates in the soil are converted to atmospheric nitrogen by
- ANitrogen-fixing bacteria
- BDenitrifying bacteriaCorrect
- CDecomposers
- DNitrifying bacteria
Show answerHide answer
Answer: B
Denitrifying bacteria convert soil nitrates back into atmospheric nitrogen gas (N₂), completing the nitrogen cycle by returning nitrogen to the air.
- A
-
10.Which of the following animals has homodont dentition?
- AMan
- BFishCorrect
- CRabbit
- DDog
Show answerHide answer
Answer: B
Homodont dentition means every tooth in the jaw is essentially the same shape and size. Fish typically have many small, uniform, conical teeth used only for gripping prey — a classic homodont arrangement.
Dog, man and rabbit are all mammals with heterodont dentition — their teeth are differentiated into incisors, canines, premolars and molars, each shaped for a different job (cutting, tearing, grinding).
- 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 2016 paper, on a timed CBT screen
Every question has the answer and an explanation, in the Skolra app.