48 questions. Try each one, then open the answer to check yourself and read the explanation.
Use the diagram to answer questions 1 and 2. The part that will develop into an organ for feeling is labelled
Answer: D (I.)
Part I is the head end of the pupa, where the antennae (organs of touch and smell) of the adult insect develop.
Use the diagram to answer questions 1 and 2. The part labelled II is the
Answer: A (silk thread)
The pupa is held to the stem by a girdle of silk thread, labelled II.
Which of the following features are all associated with monocots?
Answer: C (One seed leaf, petals in threes or groups of threes and parallel venation of leaves)
Monocots have one cotyledon, parallel leaf veins and flower parts in threes; net veins and two seed leaves belong to dicots.
The set of fins that controls steering, balancing and change of direction and pitch in fish is
Answer: B (pectoral and pelvic)
The paired pectoral and pelvic fins steer the fish, change its direction and control up-and-down tilt (pitch).
The most recently evolved structure in animals is the
Answer: A (hair)
Cilia occur in protozoa and scales in fishes, both ancient groups; hair is found only in mammals, which are treated as the most recently evolved animals.
Coelom is absent in the class of animals termed
Answer: D (coelenterata.)
Coelenterates such as Hydra have only two body layers and a single gut cavity, with no coelom.
A characteristic of vertebrates that is unique to mammals is
Answer: C (the possession of scrotum)
Pentadactyl limbs, parental care and pulmonary circulation are found in other vertebrates too, but a scrotum holding the testes outside the body is found only in mammals.
The order in which organic evolution has progressed in plants is
Answer: B (schizophyta, thallophyta, bryophyta, pteridophyta and spermatophyta)
Plant evolution runs from the simplest (schizophytes such as bacteria and blue-green algae) to algae, mosses, ferns and finally seed plants.
In which part of the human body does the secretion of the growth hormone occur?
Answer: A (Head region)
Growth hormone is made by the pituitary gland at the base of the brain, in the head.
Use the diagram to answer questions 10 and 11. The parts labelled I and II make up the
Answer: C (Malpighian body)
The knot of capillaries (glomerulus, I) inside the cup-shaped Bowman's capsule (II) together make up the Malpighian body.
Use the diagram to answer questions 10 and 11. In mammals, reabsorption of salt takes place in
Answer: B (III)
Salts are reabsorbed from the filtrate back into the blood in the convoluted tubules of the nephron.
The part of the brain that controls body posture in mammals is the
Answer: B (cerebellum)
The cerebellum co-ordinates muscles to keep balance and posture.
Peripheral arrangement of vascular tissues in dicots is a characteristic of the internal structure of the
Answer: C (stem)
In a dicot stem the vascular bundles form a ring near the outside; in the root they are in the centre.
Use the diagram to answer questions 14 and 15. The substance labelled II originates from
Answer: A (III only)
The gas (II) collecting at the top is oxygen. In photosynthesis this oxygen comes from water molecules split by light energy, and the water is the part labelled III.
Use the diagram to answer questions 14 and 15. The gas occupying the space labelled I is
Answer: D (oxygen.)
A water plant in light photosynthesises and releases oxygen, which collects at the top of the tube.
The scapula and the ischium are part of the
Answer: C (appendicular skeleton)
The scapula is in the pectoral girdle and the ischium in the pelvic girdle; both girdles belong to the appendicular skeleton.
Bacteria in the large intestine of man are important in the
Answer: A (synthesis of vitamins K and B2)
Gut bacteria in the colon make vitamin K and some B vitamins, which the body absorbs.
Short-sightedness can be corrected by lenses which are
Answer: D (concave.)
In short sight the image forms in front of the retina; a concave (diverging) lens moves it back onto the retina.
The inner ear contains two main organs, namely, the
Answer: B (cochlea and semi-circular canals)
The inner ear holds the cochlea (hearing) and the semicircular canals (balance).
For growth to occur in organisms, the rate of
Answer: C (anabolism must exceed that of catabolism)
Growth means building up more body material than is broken down, so anabolism must be faster than catabolism.
The production of violet colouration, when dilute NaOH solution is added to a solution of food substance, followed by drops of 1% CuSO4 solution while shaking indicates the presence of
Answer: A (protein)
This is the Biuret test; a violet colour shows protein.
The greatest amount of energy will be obtained by the oxidation of 100 kg of
Answer: B (butter)
Fats release about 38 kJ per gram, roughly twice as much as carbohydrates or proteins, so butter gives the most energy.
The chamber of the mammalian heart with the thickest wall is the
Answer: D (left ventricle.)
The left ventricle pumps blood round the whole body, so it has the thickest, most muscular wall.
Serum differs from blood plasma because it
Answer: C (lacks the blood protein, fibrinogen)
Serum is plasma after clotting, so its fibrinogen has been used up.
Use the diagram to answer questions 25 and 26. The part labelled II is the
Answer: A (mesocarp)
II is the thick fibrous middle layer of the fruit wall, the mesocarp.
Use the diagram to answer questions 25 and 26. The fruit represented is mainly dispersed by
Answer: B (water)
The fruit has a thick, fibrous, air-filled mesocarp, like a coconut, which lets it float and be carried by water.
In an experiment to estimate the volume of air in a soil sample using a measuring cylinder, it was found that:
Initial volume of water = p cm3
Volume of soil before mixing with water = q cm3
Final volume of water after adding soil = r cm3
From the data above, which of the following deductions is correct?
Answer: D (r < p + q.)
When soil is added, water replaces the air in its pores, so the final volume r is smaller than p + q; the difference is the volume of air.
An ecological succession often leads to
Answer: A (an increase in species diversity)
As succession proceeds, conditions become more varied and more species can live there, until a stable climax is reached.
I. High birth rate and high immigration rate II. Low birth rate and high immigration rate III. Low mortality rate and low emigration rate IV. High mortality rate and high emigration rate. Which combination of the above can cause rapid over -crowding in climax biotic communities and human settlements?
Answer: B (I and III)
Many arrivals (high births and immigration) and few losses (low deaths and emigration) make a population grow fastest.
Use the graph (plant growth against soil essential element concentration) to answer questions 31 and 32. The soil becomes toxic to plants when the concentration of its essential elements is in the range labelled
Answer: A (IV)
In range IV the concentration is so high that plant growth falls sharply, showing toxicity.
Use the graph (plant growth against soil essential element concentration) to answer questions 31 and 32. The range at which soil essential elements concentration is recorded for optimal plant growth is marked
Answer: B (III)
Range III is the flat top of the curve, where growth is highest.
Which of the following growth activities in plants is brought about by gibberellins?
Answer: C (cell elongation)
Gibberellins make stems grow taller mainly by making cells elongate.
Which of the following are adaptations of animals to aquatic habitats?
Answer: A (Gills, streamlined bodies and lateral line)
Fish breathe with gills, move easily with streamlined bodies and sense water movement with the lateral line.
Which of the following is an adaptation of forest species?
Answer: C (Buttress roots)
Tall rain forest trees have buttress roots to support them in shallow soil.
In a food chain, each succeeding level in a forward direction represents
Answer: B (a decrease in the number of individuals)
Energy is lost at every feeding level, so each level up the chain usually has fewer individuals (pyramid of numbers).
The disaster that would have the least destructive impact on animal life and balance in nature is
Answer: D (grasshopper pests.)
Grasshopper pests damage crops, but they are part of natural food webs; pollution, oil spills and fires destroy whole habitats.
The factors that determine the distribution of vegetation zones are
Answer: A (temperature, light, rain and humidity)
Climate factors, especially temperature, light, rainfall and humidity, decide which vegetation grows where.
A cross between an albino female and a genetically normal male will result in offspring that are
Answer: B (all phenotypically normal)
aa × AA gives all Aa: they look normal but carry the albino allele.
The pollutants that contribute to the depletion of the ozone layer in the atmosphere are
Answer: D (chlorofluorocarbons.)
CFCs release chlorine in the upper atmosphere, which breaks down ozone molecules.
The surest way to combine the best qualities of both parents in the offspring is by
Answer: A (cross-breeding)
Cross-breeding two different parents brings the good traits of each together in the offspring.
Blood grouping in human beings is derived from combinations of
Answer: C (three different alleles)
The ABO groups are controlled by one gene with three alleles (A, B and O); pairs of these give groups A, B, AB and O.
The older fossil-bearing rocks, in contrast to the more recent ones, are more likely to contain
Answer: B (invertebrates rather than birds)
Invertebrates evolved hundreds of millions of years before birds, so older rocks hold invertebrate fossils.
In a group of male Agama lizards, the one with the brightest head colour is the
Answer: A (dominant)
The dominant male Agama has the brightest colours to show his rank and hold his territory.
Examples of water-borne and sex-linked diseases are
Answer: D (dracunculiasis and haemophilia.)
Guinea worm is caught from drinking water, and haemophilia is inherited on the X chromosome (sex-linked).
The mutation theory of organic evolution was propounded by
Answer: B (Hugo de Vries)
Hugo de Vries proposed that new species arise through sudden changes called mutations.
A certain savanna grasshopper changes colour from green during the rainy season to brown during the dry season and black after the dry season bush fires. The reason for these colour changes is that the
Answer: C (grasshopper is avoiding predation)
By matching its background through the seasons, the grasshopper is camouflaged and less likely to be seen by predators.
Complex social behaviour and organization are found mostly in
Answer: A (insects)
Termites, bees and ants live in colonies with castes (queen, workers, soldiers) that share the work, the most complex social organisation known.
Which of the following structural features are adapted for uses other than water conservation?
Answer: D (Feathers in birds.)
Succulent stems, scales and spines all help save water, but feathers are adapted mainly for flight and insulation.