47 questions. Try each one, then open the answer to check yourself and read the explanation.
The organs that will be most useful to giant African rats in finding their way in underground habitats are the
Answer: A (vibrissae)
Vibrissae are the long sensitive whiskers. In dark burrows the rat feels its way with them, since the eyes are of little use there.
The increasing order of the particle size in the following soil types is
Answer: C (clay → silt → sand → gravel)
Clay particles are the smallest, then silt, then sand, and gravel particles are the largest.
The causative agent of bird flu is a
Answer: B (virus)
Bird flu (avian influenza) is caused by an influenza virus, for example H5N1.
Which of the following is an example of parasitism?
Answer: C (Mistletoe growing on an orange tree.)
Mistletoe sends haustoria into the orange tree and takes water and minerals from it, harming the host. Fungi on dead wood are saprophytes, and the egret and cattle both gain.
One adaptation shown by hydrophytes in freshwater habitats is the
Answer: B (poor development of roots and xylem tissues)
Water plants are surrounded by water and held up by it, so they need little root, xylem or support tissue. Spines and waxy cuticles are features of dry-land plants.
A crucible of 5 gm weighed 10 gm after filling with fresh soil. It is then heated in an oven at 100°C for 1 hour. After cooling in a desiccator, the weight was 8 gm. The percentage of water in the soil is
Answer: D (40%.)
Mass of soil = 10 − 5 = 5 g. Water lost = 10 − 8 = 2 g. Percentage of water = 2/5 × 100 = 40%.
The highest level of ecological organization is the
Answer: C (biosphere)
The levels go organism → population → community → ecosystem → biosphere. The biosphere is all the parts of the earth where life exists, so it is the highest.
The mangrove swamp in Nigeria is restricted to the
Answer: D (Tropical rainforest.)
Mangrove swamps grow along the salty coastal creeks and lagoons in the south, which lie in the tropical rainforest belt. The savannas are inland and far drier.
A biotic factor which affects the distribution and abundance of organisms in a terrestrial habitat is
Answer: B (competition)
Biotic factors come from living things, such as competition, predation and parasitism. Temperature, pH and light are abiotic (non-living) factors.
In which of the following Nigerian states can montane vegetation be found?
Answer: A (Taraba)
Montane forest and grassland grow on high plateaus such as the Mambilla Plateau in Taraba State, where it is cool and wet because of the altitude.
Use the diagram to answer: The type of protective adaptation exhibited by the animal is
Answer: C (countershading colouration)
Rats are dark on the back and pale on the belly. This countershading cancels the shadow under the body so the animal looks flat and is harder to see.
Use the diagram to answer: The structure labelled I is
Answer: D (tactile.)
I points to the whiskers. They are sensitive to touch and help the rat feel objects and openings around it.
Which of the following factors can bring about competition in a population?
Answer: C (Drought.)
Drought makes water and food scarce, so members of the population must struggle for the little that is left. Emigration and mortality reduce numbers and so reduce competition.
The theory which supports the view that the large muscles developed by an athlete will be passed on to the offspring was proposed by
Answer: A (Lamarck)
Lamarck's theory of use and disuse said that characters acquired during life are inherited. We now know acquired characters like trained muscles are not passed on.
In lizards, the lowering of the gular fold is used to
Answer: B (attract mates)
Male lizards lower and display the brightly coloured throat (gular) fold during courtship to attract females.
An example of a fish that aestivates is
Answer: C (lung fish)
When its pond dries up, the lung fish buries itself in mud inside a mucus cocoon and stays inactive (aestivates), breathing air with its lungs.
In mammals, the organ directly on top of the kidney is the
Answer: B (adrenal gland)
The adrenal glands sit like caps on top of each kidney; 'adrenal' means 'near the kidney'.
Use the diagram to answer: The diagram shows that the organisms are
Answer: C (oviparous)
The frogs are shedding eggs into the water, where the young develop outside the mother's body. Animals that lay eggs are oviparous.
Use the diagram to answer: The breeding posture illustrated in the diagram is known as
Answer: B (amplexus)
The male frog clings to the female's back with his arms while she releases eggs, which he then fertilises. This embrace is called amplexus.
The photosynthetic pigments include
Answer: A (chlorophyll and carotenoids)
Chlorophyll and carotenoids absorb light energy for photosynthesis. Chloroplasts are organelles, not pigments, and melanin and haemoglobin are animal pigments.
Use the diagram to answer: Insulin is produced by the endocrine organ labelled
Answer: B (III)
III is the pancreas in the abdomen; its islets of Langerhans make insulin, which lowers blood sugar.
Use the diagram to answer: The function of the structure labelled I is to
Answer: D (regulate the activities of other endocrine glands.)
I is the pituitary gland at the base of the brain. It is called the master gland because its hormones control other endocrine glands.
Monocot stems differ from dicot stems in that monocots have
Answer: A (no cambium)
Monocot vascular bundles are closed: they have no cambium, so monocot stems cannot undergo secondary thickening. They actually have more, scattered bundles.
The opening and closing of the stoma are regulated by
Answer: D (osmosis.)
Water enters the guard cells by osmosis, making them turgid so the pore opens. When they lose water they become flaccid and the pore closes.
Stunted growth and poor root development are a result of a deficiency in
Answer: B (phosphorus)
Phosphorus is needed for root growth and for energy transfer (ATP) in cells. Without it roots stay small and the whole plant is stunted.
The pancreas secretes enzymes for the digestion of
Answer: A (fats, proteins and carbohydrates)
Pancreatic juice contains lipase (fats), trypsin (proteins) and amylase (starch). Vitamins and minerals need no digestion and humans make no cellulase.
Pineapple is an example of
Answer: C (a composite fruit)
A pineapple forms from a whole inflorescence: the fruits of many flowers fuse into one. This is a composite (multiple) fruit.
The correct sequence of the movement of urea during urine formation is
Answer: B (glomerulus → Bowman's capsule → convoluted tubule → Henle's loop → convoluted tubule → collecting tubule)
Urea is filtered from the glomerulus into Bowman's capsule, then passes through the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule before reaching the collecting tubule.
Use the diagram to answer: Oxygenated blood is pumped to the entire body from the part labelled
Answer: A (IV)
IV is the left ventricle (on the right of the drawing). Its thick wall pumps oxygenated blood into the aorta and round the whole body.
Use the diagram to answer: The part labelled I is the
Answer: C (aorta)
I points to the large arched vessel leaving the left ventricle, which is the aorta. It carries oxygenated blood to the body.
The waste product of plants used in the conversion of hide to leather is
Answer: C (tannin)
Tannins from bark are used to tan animal hides, turning them into tough leather; this is where the word 'tanning' comes from.
Which of the following uses diffusion as the principal method of gaseous exchange?
Answer: D (Earthworm.)
The earthworm has no lungs or tracheae; oxygen simply diffuses through its thin moist skin into the blood.
Use the diagram to answer: The experiment demonstrates
Answer: A (geotropism)
On the rotating klinostat gravity acts on all sides equally and the root grows straight, while the still seedling's root bends down. This shows growth response to gravity (geotropism).
Use the diagram to answer: The part marked I will contain a high concentration of
Answer: D (auxin.)
In a root lying horizontally, gravity makes auxin collect on the lower side (I). There it slows growth, so the root curves downwards.
Use the diagram to answer: The part labelled IV is responsible for
Answer: A (osmoregulation)
IV is a star-shaped contractile vacuole of Paramecium. It collects excess water that enters by osmosis and pumps it out.
Use the diagram to answer: The organelle responsible for sexual reproduction is
Answer: D (III)
III is the small micronucleus. During conjugation (sexual reproduction) Paramecium exchanges micronuclei; the large macronucleus (II) controls everyday activities.
A water medium is necessary for fertilization in
Answer: C (ferns)
Fern sperms (antherozoids) have flagella and must swim through a film of water to reach the egg. Conifers and flowering plants use pollen tubes instead.
The chromosomes of members of the kingdom Monera are within the
Answer: B (cytoplasm)
Monera (bacteria and blue-green algae) are prokaryotes with no nuclear membrane, so their DNA lies free in the cytoplasm.
Use the diagram to answer: The organelle responsible for heredity is
Answer: A (III)
The nucleus carries the chromosomes (genes) that are passed from one generation to the next, so it controls heredity.
Use the diagram to answer: The part labelled I is the
Answer: B (cell wall)
I points to the thick outer boundary of the plant cell, the cellulose cell wall, which gives the cell its fixed shape.
The process of shedding the exoskeleton of an arthropod is known as
Answer: C (ecdysis)
Because the hard exoskeleton cannot stretch, an arthropod moults it to grow. This moulting is called ecdysis.
Which of the following is common to the mosquito, housefly and blackfly?
Answer: A (They undergo complete metamorphosis.)
All three pass through egg, larva, pupa and adult, which is complete metamorphosis. Housefly larvae live in refuse, not water, and all three are true flies with one pair of wings.
Use the diagram to answer: The process illustrated is
Answer: D (sexual reproduction in Rhizopus.)
Two hyphae of opposite strains (+ and −) meet, their gametangia fuse and form a thick-walled zygospore. This is conjugation, the sexual reproduction of Rhizopus.
Use the diagram to answer: The structure labelled I is the
Answer: C (zygospore)
I is the dark, rough-walled body formed where the two gametangia fused. It is the zygospore, which can survive bad conditions.
An accurate identification of a rapist can be carried out by conducting a
Answer: B (DNA analysis)
Each person's DNA (except identical twins) is unique, so DNA fingerprinting of samples can identify one individual. Many people share the same blood group.
Use the diagram to answer: Which of the following will be true of dog II which lost its tail in an accident if it mates with dog III?
Answer: A (None of its offspring will be born without a tail.)
Losing a tail in an accident is an acquired character; it does not change the genes. The puppies will all be born with tails.
Which of the following is true of cloning?
Answer: D (It involves the asexual multiplication of the tissues of the original organism.)
Cloning produces genetically identical copies without the fusion of gametes, so it is a form of asexual multiplication. It is still ethically controversial.