JAMB Biology 2012 Objective Past Questions

All 50 questions from the Joint Admissions and Matriculation Board (JAMB) Biology 2012 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.

Biology 2012 Objective — Question 1

Which Question Paper Type of Biology as indicated above is given to you?

• A. Type Green
• B. Type Purple
• C. Type Red
• D. Type YellowCorrect

Explanation

This is type yellow biology question.

Biology 2012 Objective — Question 2

Use the diagram below to answer questions 2 and 3. The organelle responsible for heredity is labeled

• A. I
• B. IICorrect
• C. III
• D. IV

Explanation

The structure labeled 'II' is the nucleus. The nucleus, which is the most important organelle, is responsible for heredity. It is also the chief coordinator of all the activities of a cell.

Biology 2012 Objective — Question 3

(Using the same diagram as Q2) The part labeled IV is the

• A. mitochondrionCorrect
• B. cell wall
• C. endoplasmic reticulum
• D. nucleus

Explanation

The part labeled 'IV' is endoplasmic reticulum. It is worthy of notice that the endoplasmic reticulum occurs in two forms — if it has ribosomes attached to its surface, it is a Rough Endoplasmic Reticulum, if it doesn't, it is a Smooth Endoplasmic Reticulum.

Biology 2012 Objective — Question 4

Which of the following is most advanced in the evolutionary trend of animals?

• A. Liver fluke
• B. Earthworm
• C. Snail
• D. CockroachCorrect

Explanation

The evolutionary trend among invertebrates is: Protozoa→Coelenterata→Platyhelminthess→Nematode→Annelida→Mollusca→Arthropoda→Echinodermata. Liverfluke is a platyhelminthe, earthworm is an annelid, snail is a molluscan while cockroach is an arthropod. It is crystal clear that the cockroach is the most advanced.

Biology 2012 Objective — Question 5

Which of the following is the lowest category of classification?

• A. Class
• B. speciesCorrect
• C. family
• D. genus

Explanation

The species is the lowest category of classification; the kingdom is the highest category. The hierarchy goes as: Kingdom→Phylum (or division for plant)→Class→Order→Family→Genus→Species.

Biology 2012 Objective — Question 6

Plants that show secondary growth are usually found among the

• A. thallophytes
• B. pteridophytes
• C. monocotyledons
• D. dicotyledonsCorrect

Explanation

Secondary growth or secondary thickening is characteristic of dicotyledonous plants. A plant that shows secondary growth or thickening grows both in height and width.

Biology 2012 Objective — Question 7

The fungi are a distinct group of eukaryotes mainly because they have

• A. spores
• B. no chlorophyllCorrect
• C. many fruiting bodies
• D. sexual and asexual reproduction

Explanation

It is not lack of chlorophyll that makes fungi unique (many organisms lack chlorophyll). Nor is it possession of spores, or common sexual/asexual reproduction (both widespread across organisms). The unique feature of fungi is the possession of many fruiting bodies.

Biology 2012 Objective — Question 8

An arthropod that is destructive at the early stage of its lifecycle is

• A. butterflyCorrect
• B. mosquito
• C. bee
• D. millepede

Explanation

The young forms of butterflies (known as the caterpillars) are plant pests.

Biology 2012 Objective — Question 9

An animal body that can be cut along its axis in any plane to give two identical parts is said to be a

• A. radially symmetrical bodyCorrect
• B. bilaterally symmetrical body
• C. asymmetrical body
• D. symmetrical body

Explanation

A radially symmetrical body is one that can be cut along its axis in any plane to give two identical parts.

Biology 2012 Objective — Question 10

Which of the following possesses mammary gland?

• A. Dogfish
• B. WhaleCorrect
• C. Shark
• D. Catfish

Explanation

The possession of mammary gland and hair distinguishes mammals from other groups of animals. Dogfish, Shark and Catfish are fishes while Whale, though aquatic, is a mammal.

Biology 2012 Objective — Question 11

The feature that links birds to reptiles in evolution is possession of

• A. feathers
• B. beak
• C. skeleton
• D. scalesCorrect

Explanation

The possession of scales links birds to reptiles. Recall that birds are next to reptiles in the vertebrate evolutionary trend: Pisces→Amphibians→Reptiles→Aves (Birds)→Mammals.

Biology 2012 Objective — Question 12

Counter shading is an adaptive feature that enables animals to

• A. fight enemies
• B. remain undetected in its environment, with this it can escape predationCorrect
• C. warn enemies
• D. attract mates

Explanation

Counter shading is an adaptation for protection. It enables an animal to remain undetected in its environment, with this it can escape predation.

Biology 2012 Objective — Question 13

Which of the following plant structures lacks a waterproof cuticle?

• A. Leaf
• B. Stem
• C. RootCorrect
• D. Shoot

Explanation

The root does not have a water-proof cuticle. If roots had water-proof cuticles, the absorption of water from the soil would be impossible.

Biology 2012 Objective — Question 14

In the mammalian male reproductive system, the part that serves as a passage for both urine and semen is the

• A. urethraCorrect
• B. ureter
• C. bladder
• D. seminal vesicle

Explanation

The urethra is urinogenital in function — it serves as a passage for both urine and semen. The urethra should not be confused for the ureter, which is a structure that passes urine from the kidney to the bladder.

Biology 2012 Objective — Question 15

In plants, which of the following is required in minute quantities for growth?

• A. CopperCorrect
• B. Potassium
• C. Phosphorus
• D. Sodium

Explanation

Elements needed in large quantities are called major elements or macronutrients (e.g. Potassium, Sodium, Phosphorus) while those needed in small quantities are called minor elements or micronutrients, such as Copper, Molybdenum, Zinc, Manganese and Boron.

Biology 2012 Objective — Question 16

Which of the following organisms is both parasitic and autotrophic?

• A. Sundew
• B. LoranthusCorrect
• C. Rhiopus
• D. Tapeworm

Explanation

Insectivorous plants like Sundew can photosynthesize but they trap insects to obtain nitrogen, since they are typically found in nitrogen-poor soils. Loranthus is a parasitic plant that can also photosynthesize (autotrophic).

Biology 2012 Objective — Question 17

A function of the hydrochloric acid produced in the human stomach during digestion is to

• A. neutralize the effect of bile
• B. coagulate milk protein and emulsify fats
• C. stop the action of ptyalinCorrect
• D. break up food into smaller particles

Explanation

The HCl produced in the stomach kills germs, provides an acidic environment for gastric enzymes, and neutralizes the alkalinity of saliva. Since the enzyme ptyalin present in saliva only works in an alkaline medium, once HCl neutralizes that alkalinity, the action of ptyalin is stopped.

Biology 2012 Objective — Question 18

Which of the following is a polysaccharide?

• A. Glucose
• B. Sucrose
• C. Maltose
• D. CelluloseCorrect

Explanation

Glucose, galactose, fructose and mannose are monosaccharides. Sucrose, maltose and lactose are disaccharides. Starch and cellulose are polysaccharides.

Biology 2012 Objective — Question 19

Use the diagram below to answer questions 19 and 20. Transportation in the xylem is represented by

• A. I
• B. II
• C. III
• D. IVCorrect

Explanation

The xylem transports water and mineral salts from the soil upwards (as shown by 'IV'). The phloem transports food substances from the leaf to other parts of the plant (as shown by 'I').

Biology 2012 Objective — Question 20

(Using the same diagram as Q19) The arrow labeled II represents the

• A. release of oxygenCorrect
• B. intake of carbon (IV) oxide
• C. movement of photosynthates
• D. movement of nutrients

Explanation

The arrow labeled 'II' depicts the release of oxygen into the environment. This happens during photosynthesis.

Biology 2012 Objective — Question 21

In the kidney of mammals, the site of ultrafiltration is the

• A. uriniferous tubule
• B. Bowman's capsuleCorrect
• C. loop of Henle
• D. renal tubule

Explanation

Ultrafiltration occurs in the Bowman's capsule.

Biology 2012 Objective — Question 22

Which of the following is involved in secondary thickening in plants?

• A. Collenchyma and xylem cells
• B. Vascular cambium and collenchyma cells
• C. Vascular cambium and cork cambiumCorrect
• D. Cork cambium and sclerenchyma

Explanation

In gymnosperms and dicotyledons, growth does not only take place by the activities of apical root, apical stem and intercalary meristems but also by the activities of the vascular cambium and cork cambium to bring about increase in the diameter of the roots and stem. This is known as secondary growth.

Biology 2012 Objective — Question 23

An example of a fruit that develops from a single carpel is

• A. okro
• B. tomato
• C. beanCorrect
• D. orange

Explanation

A legume is a simple fruit that develops from a superior monocarpous pistil; bean is a legume.

Biology 2012 Objective — Question 24

Use the diagram to answer questions 24 and 25. The developing embryo is usually contained in the part labeled

• A. I
• B. IV
• C. IICorrect
• D. III

Explanation

The developing embryo is usually contained in the part labeled 'II'. The part is known as the uterus or womb.

Biology 2012 Objective — Question 25

(Using the same diagram as Q24) The function of the part labeled III is to

• A. produce egg cellsCorrect
• B. protect sperms during fertilization
• C. secrete hormones during coitus
• D. protect the developing embryo

Explanation

The part labeled 'III' is the ovary. The ovary produces egg cells.

Biology 2012 Objective — Question 26

Plant growth can be artificially stimulated by the addition of

• A. gibberellinCorrect
• B. kinin
• C. abscisic acid
• D. ethylene

Explanation

Plant growth can be artificially stimulated by the addition of gibberellin, which stimulates the growth of root and stem.

Biology 2012 Objective — Question 27

The autonomic nervous system consists of neurons that control the

• A. voluntary muscles
• B. heart beatCorrect
• C. tongue
• D. hands

Explanation

The autonomic nervous system is concerned with involuntary body activities e.g. breathing, heart beat etc.

Biology 2012 Objective — Question 28

Plants of temperate origin can be grown in tropical areas in the vegetation zones of the

• A. rain forest
• B. Guinea savanna
• C. Sudan savanna
• D. montane forestCorrect

Explanation

Plants of temperate origin can do well in tropical areas in the vegetation zones of the montane forest, given the cooler high-altitude conditions there (per the printed answer key).

Biology 2012 Objective — Question 29

The water cycle is maintained mainly by

• A. evaporation of water in the environment
• B. evaporation and condensation of water in the environmentCorrect
• C. condensation of water in the environment
• D. transpiration and respiration in plants

Explanation

The water cycle is maintained mainly by evaporation and condensation of water in the environment.

Biology 2012 Objective — Question 30

Organisms living in an estuarine habitat are adapted to

• A. withstand wide fluctuations in temperature
• B. survive only in water with low salinity
• C. withstand wide fluctuations in salinityCorrect
• D. feed only on phytoplankton and dead organic matter

Explanation

Organisms living in an estuarine habitat are adapted to withstand wide fluctuations in salinity.

Biology 2012 Objective — Question 31

The presence of stilt roots, pneumatophores, sunken stomata and salt glands are adaptive features of plants found in the

• A. tropical rainforest
• B. mangrove swampsCorrect
• C. grassland
• D. montane forest

Explanation

The presence of stilt roots, pneumatophores, sunken stomata and salt glands are adaptive features of plants found in the mangrove swamps.

Biology 2012 Objective — Question 32

Which of the following animals can exist solely on the water they get from food and metabolic reactions?

• A. Forest arboreal dwellers
• B. Desert dwellersCorrect
• C. Forest ground dwellers
• D. Rainforest dwellers

Explanation

Desert dwellers can exist solely on the water they get from food and metabolic reactions, due to their adaptation to arid conditions.

Biology 2012 Objective — Question 33

The most likely first colonizers of a bare rock are

• A. mosses
• B. ferns
• C. lichenCorrect
• D. fungi

Explanation

The most likely first colonizers of a bare rock are lichen.

Biology 2012 Objective — Question 34

The carrying capacity of a habitat is reached when the population growth begins to

• A. increase slowly
• B. increase exponentially
• C. slow down
• D. remain steadyCorrect

Explanation

The carrying capacity of a habitat is reached when the population growth begins to remain steady.

Biology 2012 Objective — Question 35

The abiotic factors that control human population include

• A. disease and famine
• B. space and rainfallCorrect
• C. flooding and earthquake
• D. temperature and disease

Explanation

The abiotic factors that control human population include space and rainfall (per the printed key).

Biology 2012 Objective — Question 36

An indigenous method of renewing and maintaining soil fertility is by

• A. clearing farms by burning
• B. planting one crop type
• C. adding inorganic fertilizers yearly
• D. crop rotation and shifting cultivationCorrect

Explanation

An indigenous method of renewing and maintaining soil fertility is by crop rotation and shifting cultivation.

Biology 2012 Objective — Question 37

The diseases caused by water-borne pathogens include

• A. gonorrhoea and poliomyelitis
• B. typhoid and syphilis
• C. tuberculosis and cholera
• D. typhoid and choleraCorrect

Explanation

Typhoid and cholera are caused by water-borne pathogens (unlike gonorrhoea, poliomyelitis, syphilis and tuberculosis).

Biology 2012 Objective — Question 38

Use the diagram below to answer questions 38 and 39. The graph illustrates

• A. the highest frequency for height of 2 metres
• B. a discontinuously varying character
• C. a continuously varying characterCorrect
• D. total yield in a cassava farm

Explanation

The graph illustrates a continuously varying character.

Biology 2012 Objective — Question 39

(Using the same diagram as Q38) The largest number of cassava plants has an approximate height of

• A. 1.4m
• B. 1.6mCorrect
• C. 1.8m
• D. 2.0m

Explanation

From the graph, the peak (largest number of cassava plants) corresponds to an approximate height of 1.6m.

Biology 2012 Objective — Question 40

Which of the following is true in blood transfusion?

• A. A person of blood group AB can donate blood only to another person of blood group AB
• B. Persons of blood groups A and B can donate or receive blood from each otherCorrect
• C. A person of blood group AB can receive blood only from persons of blood group O
• D. A person of blood group O can donate only to a person of blood group O

Explanation

Persons of blood groups A and B can donate or receive blood from each other, since a valid donor-recipient combination exists between certain groups (per the printed answer key).

Biology 2012 Objective — Question 41

A yellow maize is planted and all the fruits obtained are of yellow seeds. When they are cross-bred, yellow seeds and white seeds are obtained in a ratio 3:1. The yellow seed is said to be a

• A. non-heritable trait
• B. sex-linked trait
• C. recessive trait
• D. dominant traitCorrect

Explanation

A 3:1 ratio when crossed indicates that the yellow seed colour is a dominant trait.

Biology 2012 Objective — Question 42

When a colour-blind man marries a carrier woman. What is the probability of their offspring being colour blind?

• A. 25%
• B. 50%Correct
• C. 75%
• D. 100%

Explanation

The probability of their offspring being colour blind is 50%.

Biology 2012 Objective — Question 43

The correct base pairing for DNA is

• A. adenine → thymine and guanine →cytosineCorrect
• B. adenine → guanine and thymine → cytosine
• C. adenine → cytosine and guanine → thymine
• D. adenine → adenine and cytosine → cytosine

Explanation

Guanine will always pair with cytosine while thymine always pairs with adenine.

Biology 2012 Objective — Question 44

Use the diagram below to answer questions 44 and 45. The type of interaction shown is referred to as

• A. interspecific competitionCorrect
• B. intraspecific competition
• C. mutualism
• D. cooperation

Explanation

Interspecific competition involves organisms of different species while intraspecific competition involves those of the same species. P. Aurelia and P. caudatum are two different species of paramecium.

Biology 2012 Objective — Question 45

(Using the same diagram as Q44) Which of the following statement is correct about the interaction?

• A. P. aurelia is better adapted for obtaining food than P. caudatumCorrect
• B. P. cuvdatum is better adapted for obtaining food than P. Aurelia
• C. Both organisms cannot coexist
• D. Both organisms cannot reproduce

Explanation

Since P. aurelia occurs in greater number than P. caudatum, the former is better adapted than the latter.

Biology 2012 Objective — Question 46

The short thick beak in birds is an adaptation for

• A. crushing seedsCorrect
• B. sucking nectar
• C. tearing flesh
• D. straining mud

Explanation

Short thick beaks are adapted for crushing seeds. Long, narrow and tubular beaks are for sucking liquid food. Flattened and broad beaks with grooved sides are for sifting out food from water and mud.

Biology 2012 Objective — Question 47

The basking of Agama lizards in the sun is to

• A. chance the colour of their body
• B. raise their body temperature to become activeCorrect
• C. fight to defend their territories
• D. attract the female for courtship

Explanation

The basking of Agama lizards in the sun is to raise their body temperature to become active.

Biology 2012 Objective — Question 48

The significance of a very large number of termites involved in nuptial swarming is to

• A. provide birds with plenty of food
• B. ensure their perpetuation despite predatory pressureCorrect
• C. search for a favourable place to breed
• D. ensure that every individual gets a mate

Explanation

The significance of a very large number of termites involved in nuptial swarming is to ensure their perpetuation despite predatory pressure.

Biology 2012 Objective — Question 49

The use and disuse of body parts and the inheritance of acquired traits were used to explain

• A. Darwin's theory
• B. Lamarck's theoryCorrect
• C. genetic drift
• D. gene flow

Explanation

The use and disuse of body parts and the inheritance of acquired traits were used to explain Lamarck's theory.

Biology 2012 Objective — Question 50

From his study of Galapagos finches, Darwin derived his theory of evolution from

• A. comparative anatomyCorrect
• B. comparative physiology
• C. fossil remains
• D. comparative embryology

Explanation

Darwin observed that the finches had dissimilar beaks. He therefore concluded that natural selection shaped the beaks differently. Since anatomy deals with body structures, it can be said that he derived his theory of evolution from comparative anatomy.