All 40 questions from the Joint Admissions and Matriculation Board (JAMB) Biology 2020 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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1. Which of the following types of skeleton does a cockroach possess?
Exoskeleton is the type of skeleton found on the external part of the body of some insects, snails, prawns, crabs, spiders, crayfish etc.
2. Hypermetropia is same as ___ and is corrected with the use of ___
Hypermetropia is same as long-sightedness and is corrected with the use of converging (convex) lens.
3. Which of the following is not an autotrophy?
Chlamydomonas, Zea mays & Mangifera indica are green plants. They are thus autotrophs since they can manufacture their own food. Mushroom is a fungus; it cannot manufacture its own food since it does not possess chlorophyll, so it is not an autotroph — it is a heterotroph.
4. A leaf of a particular plant was plucked. Upon examination, the veins on the leaf are found to be parallel to one another. Which of the following is likely to be the plant?
Maize is a monocotyledonous plant while others are dicotyledonous plants. Note that while dicot plants possess net venation, monocot plants possess parallel venation.
5. Which of the following does not have three pairs of legs?
Spider (an arachnid) has four pairs of legs while insects (cockroach, housefly, cricket, etc.) have three pairs of legs.
6. The sex(gender) of a baby is determined during ___ (a) copulation (b) ovulation ( ) fertilization (d) gestation
The gender of a baby is determined during fertilization. If the sperm that fertilizes the egg is of X-chromosome, the baby will be female, and if Y-chromosome, the baby will be male.
7. The following are parts of a feather except
Barbule, vane and aftershaft are parts of a feather while a wing contains many feathers.
8. Which of the following is a water soluble vitamin?
Vitamins A, D, E and K are fat-soluble vitamins. Vitamins B and C are water-soluble vitamins.
9. The only blood vessel that begins and ends with a capillary is the
The hepatic portal vein is the only blood vessel that begins and ends with a capillary.
10. The secchi disc is used in the measurement of (a) turbidity (b) waves (c ) tides (d) rain fall
The secchi disc is used in the measurement of turbidity of water.
11. Which of the following organelles is common to both plant and animal cells?
Organelles common to both plant and animal cells are nucleus, mitochondria, cytoplasm, cell membrane, lysosome, ribosomes, endoplasmic reticulum, Golgi bodies etc. Plant cells have no centrioles and centrosomes; animal cells have no chloroplast and cell wall.
12. The following are excretory products except (a) faces (b) sweat (c) CO2 (d) urine
Faeces is not an excretory product; it is an undigested food substance. Instead, it can be called an egestory product.
13. Bacteria which free soil nitrogen are called (a) nitrating bacteria (b) denitrifying bacteria (c) nitrifying bacteria (d) nitrogen-fixing bacteria
Bacteria which free soil nitrogen are called denitrifying bacteria. They convert the nitrogen in the soil to atmospheric nitrogen, a good example being pseudomonas.
14. Coagulation of milk proteins is done by (a) ptyalin (b) trypsin (c) rennin (d) pepsin
Coagulation/curdling of milk proteins is done by rennin. It does this by converting the soluble milk protein (caseinogen) to insoluble milk protein (casein).
15. The phenotypic ratio of the offspring obtained from a cross between a tall plant and a heterozygous tall plant is (a) 1:3 (b) 2:1 (c) 1:1 (d) 3:1
Cross of Tt x Tt gives genotypic ratio 1 TT : 2 Tt : 1 tt, and phenotypic ratio 3 tall : 1 short (tall:short = 3:1).
16. Which of the following animals lack canine? (a) Rabbit (b) Lion (c) Man (d) Dog
Canine is primarily used for tearing flesh. Since herbivores (like rabbit) do not feed on flesh, they have no use for canine, and therefore lack it.
17. In which of the following does the conversion of excess amino acids into urea occur? (a) Liver (b) Kidney (c) Pancreas (d) Villi
Excess amino acid is converted to urea through the process of deamination, which occurs in the liver. This should not be confused with urine formation, which occurs in the kidney.
18. The following are tests for protein except (a) Biuret test (b) Osmic acid test (c) Millon's test (d) Xanthoproteic test
Osmic acid test is a test for fats and oils while Biuret test, Millon's test and Xanthoproteic test are for protein.
19. Which of the following diseases groups contains diseases caused by bacteria? (a) Syphillis, gonorrhea (b) Tuberculosis, polio (c) Tuberculosis, small pox (d) Measles, gonorrhoea
Syphilis, gonorrhea and tuberculosis are caused by bacteria. Small pox and poliomyelitis are caused by viruses.
20. The character shown by an organism is due to the effects of (a) hormones (b) hormones and chromosomes (c) chromosomes (d) genes and environment
The character displayed by an organism is the interplay of the gene and the environment.
21. The power of accommodation of the human eye is controlled by the (a) ciliary muscles (b) cornea (c) lens (d) aqueous humor
Accommodation is the ability of the eye to see near and distant objects clearly. It is controlled by the ciliary muscles.
22. A person whose blood can be donated to all other people must have the blood type (a) O (b) AB (c) A (d) B
O is the universal donor while AB is the universal recipient.
23. Which of the following is/are the product(s) of sucrose hydrolysis? (a) Glucose (b) Glucose and gelatos (c) Glucose and Fructose (d) Mannose
The hydrolysis of sucrose yields glucose and fructose. The hydrolysis of maltose yields glucose (1 unit of maltose yields 2 units of glucose). The hydrolysis of lactose yields glucose and galactose.
24. In what part of a leguminous plant can a bacterium like Rhizobium leguminosarium be found? (a) Root nodules (b) spongy mesophyll of leaf (c) palisade mesophyll of leaf (d) Internodes
Rhizobium leguminosarium is a symbiotic nitrogen-fixing bacterium. It inhabits the root nodules of leguminous plants; it gets food and shelter and in turn helps the plant in nitrogen fixation.
25. If a plant can grow in the desert, it is called a/an ___ (a) mesophyte (b) epiphyte (c) xerophytes (d) hydrophyte
Xerophytes are plants that grow in regions with limited supply of water. Hydrophytes grow in fresh water; halophytes grow in salty water; epiphytes grow on other plants without causing harm to the host plant; mesophytes are plants that grow in regions with moderate supply of water.
26. Which of the following is incorrect? (a) Blood in the pulmonary artery is richer in oxygen than that in the pulmonary vein (b) Arteries are thicker and larger than veins (c) The hepatic portal vein is the richest vein when it comes to food substances (d) None of the above
It is the blood in the pulmonary vein that is richer in oxygen than that in the pulmonary artery — the pulmonary artery transports deoxygenated blood from the heart to the lungs (for oxygenation) while the pulmonary vein returns the oxygenated blood to the heart.
27. Which of the following is/are non-seed-producing plants except (a) mosses (b) bryophytes (e.g bryophytes) algae (c) pteridophytes (e.g ferns) (d) liverwort
Schizothymes, thallophytes (e.g algae), bryophytes (mosses & liver worts) and pteridophytes (e.g ferns) are non-seed producing plants. Spermatophytes (angiosperms and gymnosperms) are seed-producing plants. Whistling pine is an example of gymnosperms.
28. The elements required for chlorophyll formation are (a) magnesium, iron and nitrogen (b) potassium and nitrogen (c) magnesium and calcium (d) None of the above
The elements required for chlorophyll formation are magnesium, iron and nitrogen. Thus, yellowing of leaves (chlorosis) is a symptom of the deficiency of any of those elements.
29. Saprophytism involves (a) only one organism (b) two organisms (c) three organisms (d) many organisms
Saprophytism involves only one organism since a saprophyte obtains its nutrient from the remains of plants and animals.
30. The two strands of chromosomes (the sister chromatids) are joined at a point known as the (a) centromere (b) telomere (c) spindle (d) chromatid
The two strands of chromosomes (the sister chromatids) are joined at a point known as the centromere.
31. Muscles are attached to bones by means of (a) tendons (b) ligaments (c) sutures (d) filaments
Muscles are attached to bones by means of tendons; bones are held to bones by ligaments.
32. Plants store carbohydrate as (a) starch (b) fructose (c) galactose (d) cellulose
Plants store carbohydrate as starch while animals and fungi store carbohydrate as glycogen.
33. The hormones required for blood sugar regulation are produced in the (a) liver (b) pituitary gland (c) pancreas (d) kidney
The hormones required for blood sugar regulation (insulin and glucagon) are produced in the pancreas.
34. Carbon monoxide poisons tissues by (a) combining with haemoglobin, destroying blood vessels (b) killing the cells (c) turning the blood black (d) combining with haemoglobin, reducing oxygen transportation
Carbon monoxide poisons tissues by combining with haemoglobin. The effect of this is that less haemoglobin will be available for oxygen transportation. This may lead to suffocation and eventual death.
35. Height, weight and skin colour are examples of continuous variation while the ability to roll the tongue is a
Height, weight and skin colour are examples of continuous variation while the ability to roll the tongue is a discontinuous variation.
36. Warm-blooded animals are said to be (a) homeothermic (b) poikilothermic (c) polythermic (d) homeostatic
Warm-blooded animals (e.g mammals) are called homeothermic animals while cold-blooded animals are called poikilothermic animals.
37. The oxygen released during photosynthesis is from (a) CO2 (b) enzymes (c) water (d) hydrogen ions
The oxygen released during photosynthesis has been demonstrated to come from water: H2O -> H+ + OH-, 4OH- -> 2H2O + O2 + 4e-.
38. Which of the following is not a direct consequence of the greenhouse effect? (a) global warming (b) water pollution (c) melting of ice caps (d) increase in land temperature
Global warming, melting of ice caps, and increase in land temperature are direct consequences of the greenhouse effect. Water pollution is not a direct consequence.
39. The appendicular skeleton comprises (a) limbs and skull (b) pectoral girdle and spinal cord (c) limbs and hid limb girdles (d) sternum, vertebral column, ribs and skull
The appendicular skeleton comprises the limbs (fore limb and hind limb) and limb girdles (pelvic girdle and pectoral girdle).
40. Insects visit flowers in order to (a) pollinate the flowers (b) deposit pollen on the stigma (c) feed on the nectar (d) pluck away some anthers
Although some flowers are pollinated by insects (entomophilous flowers), the intent of these insects is not to pollinate the flowers. The insects visit flowers to feed on their nectar, but also end up pollinating the flower during this process.
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