47 questions. Try each one, then open the answer to check yourself and read the explanation.
Use the diagram to answer: The part labelled IV is the
Answer: C (endoplasmic reticulum)
IV points to the folded membranes in the cytoplasm, the endoplasmic reticulum. This is an animal-type cell, so it has no cell wall.
Which of the following is most advanced in the evolutionary trend of animals?
Answer: D (Cockroach.)
Arthropods such as the cockroach have jointed legs, an exoskeleton and a well-developed nervous system, so they are more advanced than flatworms, annelids and molluscs.
Which of the following is the lowest category of classification?
Answer: B (Species.)
The order is kingdom, phylum, class, order, family, genus, species, so species is the lowest (smallest) group.
Plants that show secondary growth are usually found among the
Answer: D (dicotyledons.)
Dicotyledons have a cambium between xylem and phloem that keeps dividing, so their stems and roots grow thicker (secondary growth). Monocots usually have no cambium.
The fungi are a distinct group of eukaryotes mainly because they have
Answer: B (no chlorophyll)
Fungi cannot make their own food because they lack chlorophyll; they feed on dead or living matter. Spores are also made by mosses and ferns, so spores do not set fungi apart.
An arthropod that is destructive at the early stage of its life cycle is
Answer: A (butterfly)
The butterfly's larva (caterpillar) feeds heavily on leaves and damages crops, while the adult only sips nectar.
An animal body that can be cut along its axis in any plane to give two identical parts is said to be
Answer: A (radially symmetrical)
In radial symmetry (e.g. Hydra, starfish) any cut through the central axis gives two similar halves; bilateral symmetry allows only one such cut.
Which of the following possesses mammary gland?
Answer: B (Whale.)
The whale is a mammal, so the female has mammary glands to feed her young with milk. The others are fishes.
The feature that links birds to reptiles in evolution is the possession of
Answer: D (scales.)
Birds still have scales on their legs and feet, like reptiles, which shows that birds evolved from reptile ancestors.
Countershading is an adaptive feature that enables animals to
Answer: B (remain undetected)
In countershading the back is dark and the belly is pale, which cancels out shadows so the animal blends in and is hard to see.
Which of the following plant structures lacks a waterproof cuticle?
Answer: C (Root.)
Roots must absorb water from the soil, so they have no waterproof cuticle; a cuticle covers the parts above ground to reduce water loss.
In the mammalian male reproductive system, the part that serves as a passage for both urine and semen is the
Answer: A (urethra)
In males the urethra runs through the penis and carries urine from the bladder and also semen during ejaculation.
In plants, which of the following is required in minute quantities for growth?
Answer: A (Copper.)
Copper is a micronutrient (trace element) needed only in tiny amounts; potassium and phosphorus are macronutrients needed in large amounts.
Which of the following organisms is both parasitic and autotrophic?
Answer: B (Loranthus)
Loranthus is a green partial parasite: it takes water and minerals from its host with haustoria but makes its own food by photosynthesis.
A function of the hydrochloric acid produced in the human stomach during digestion is to
Answer: C (stop the action of ptyalin)
Ptyalin (salivary amylase) works only in neutral to slightly alkaline conditions; the acid in the stomach stops it working and gives pepsin the acid it needs.
Which of the following is a polysaccharide?
Answer: D (Cellulose.)
Cellulose is made of many glucose units joined together, so it is a polysaccharide. Glucose is a monosaccharide; sucrose and maltose are disaccharides.
Use the diagram (arrows represent directional movement of materials) to answer: Transportation in the xylem is represented by
Answer: D (IV)
Xylem carries water and mineral salts upwards from the root to the leaves; in the diagram the upward arrow in the stem is labelled IV.
In the kidney of mammals, the site of ultrafiltration is the
Answer: B (Bowman's capsule)
Blood is filtered under high pressure from the glomerulus into the Bowman's capsule; this is ultrafiltration.
Which of the following is involved in secondary thickening in plants?
Answer: C (Vascular cambium and cork cambium.)
Secondary thickening comes from two dividing layers: the vascular cambium makes new xylem and phloem, and the cork cambium makes the bark.
An example of a fruit that develops from a single carpel is
Answer: C (bean)
A bean pod (legume) develops from one carpel. Okro, tomato and orange develop from ovaries made of several fused carpels.
Use the diagram to answer: The developing embryo is usually contained in the part labelled
Answer: C (II)
Part II is the uterus (womb), where the embryo implants and develops.
Use the diagram to answer: The function of the part labelled III is to
Answer: A (produce egg cells)
Part III is the ovary, which produces egg cells (ova) as well as female hormones.
Plant growth can be artificially stimulated by the addition of
Answer: A (gibberellin)
Gibberellins are growth hormones that make stems lengthen, so farmers spray them to boost growth. Abscisic acid and ethylene slow growth or cause ripening and leaf fall.
The autonomic nervous system consists of neurons that control the
Answer: B (heart beat)
The autonomic nervous system controls involuntary actions such as heartbeat, breathing and digestion, not muscles we move at will.
Plants of temperate origin can be grown in tropical areas in the vegetation zones of the
Answer: D (montane forest.)
Montane forests are on high land (e.g. Jos, Obudu, Mambilla), where it is cool like temperate regions, so temperate crops grow well there.
The water cycle is maintained mainly by
Answer: B (evaporation and condensation of water in the environment)
Water evaporates, then condenses into clouds and falls as rain; evaporation and condensation together keep the cycle going.
Organisms living in an estuarine habitat are adapted to
Answer: C (withstand wide fluctuations in salinity)
An estuary is where river (fresh) water meets sea water, so the salt content changes with the tides; its organisms must tolerate large changes in salinity.
The presence of stilt roots, pneumatophores, sunken stomata and salt glands are adaptive features of plants found in the
Answer: B (mangrove swamps)
Mangrove plants live in salty, waterlogged mud: stilt roots hold them up, pneumatophores take in air and salt glands get rid of excess salt.
Which of the following animals can exist solely on the water they get from food and metabolic reactions?
Answer: B (Desert dwellers.)
Desert animals such as the kangaroo rat rarely find water to drink, so they survive on water in their food and water made during respiration (metabolic water).
The most likely first colonizers of a bare rock are
Answer: C (lichen)
Lichens can grow on bare rock with no soil; they slowly break the rock down and start soil formation, so they are the pioneer colonizers.
The carrying capacity of a habitat is reached when the population growth begins to
Answer: D (remain steady.)
At the carrying capacity the habitat can support no more individuals, so births balance deaths and the population size stays steady.
The abiotic factors that control human population include
Answer: C (flooding and earthquake)
Abiotic factors are non-living. Floods and earthquakes are physical events that kill people, while disease and famine involve living things (pathogens, food).
An indigenous method of renewing and maintaining soil fertility is by
Answer: D (crop rotation and shifting cultivation.)
Traditional farmers rotate crops and leave land to rest (shifting cultivation), which lets the soil recover its nutrients naturally.
The diseases caused by waterborne pathogens include
Answer: D (typhoid and cholera.)
Typhoid and cholera bacteria spread through contaminated drinking water. Gonorrhoea and syphilis are sexually transmitted and tuberculosis is airborne.
Use the graph of frequency against height of cassava in metres to answer: The graph illustrates
Answer: C (a continuously varying character)
Height takes a full range of values and gives a smooth bell-shaped curve, which is typical of continuous variation.
Use the graph of frequency against height of cassava in metres to answer: The largest number of cassava plants has an approximate height of
Answer: B (1.6m)
The peak of the curve, where frequency is highest, is above about 1.6 m on the height axis.
Which of the following is true in blood transfusion?
Answer: A (A person of blood group AB can donate blood only to another person of blood group AB.)
Group AB blood carries both A and B antigens, so only an AB recipient (with no anti-A or anti-B antibodies) can safely receive it. Group O is the universal donor and AB the universal recipient.
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
Answer: D (a dominant trait.)
A 3:1 ratio in the offspring of two hybrids is Mendel's ratio: the trait that shows in 3 out of 4 (yellow) is dominant and white is recessive.
When a colour-blind man marries a carrier woman. What is the probability of their offspring being colour blind?
Answer: B (50%)
XcY × XCXc gives XCXc, XcXc, XCY and XcY. Two of the four (XcXc and XcY) are colour blind, so 50%.
The correct base pairing for DNA is
Answer: A (adenine → thymine and guanine → cytosine)
In DNA, adenine always pairs with thymine and guanine always pairs with cytosine.
Use the graph of number of organisms of P. aurelia and P. caudatum against time (days) to answer: The type of interaction shown is referred to as
Answer: A (interspecific competition)
Two different species compete for the same food; one increases while the other declines. Competition between different species is interspecific.
Use the graph of number of organisms of P. aurelia and P. caudatum against time (days) to answer: Which of the following statements is true of the interaction?
Answer: A (P. aurelia is better adapted for obtaining food than P. caudatum.)
The P. aurelia population keeps rising while P. caudatum falls, so P. aurelia wins the competition for food.
The short thick beak in birds is an adaptation for
Answer: A (crushing seeds)
Seed-eating birds such as weaver birds have short, strong, thick beaks for cracking hard seeds.
The basking of Agama lizards in the sun is to
Answer: B (raise their body temperature to become active)
The Agama lizard is cold-blooded, so its body temperature depends on its surroundings; it lies in the sun to warm up before it can move about actively.
The significance of a very large number of termites involved in nuptial swarming is to
Answer: B (ensure their perpetuation despite predatory pressure)
Many swarming termites are eaten by birds, lizards and people; releasing huge numbers makes sure that enough survive to start new colonies.
The use and disuse of body parts and the inheritance of acquired traits were used to explain
Answer: B (Lamarck's theory)
Lamarck said organs grow with use and shrink with disuse, and that such acquired changes are passed on to offspring.
From his study of Galapagos finches, Darwin derived his theory of evolution from
Answer: A (comparative anatomy)
Darwin compared the different beak shapes and sizes of living finches on the Galapagos islands, each suited to its food; comparing body structures is comparative anatomy.