47 questions. Try each one, then open the answer to check yourself and read the explanation.
On what structures are the units of inheritance situated?
Answer: C (Chromosomes)
Genes, the units of inheritance, are carried along the chromosomes in the nucleus.
Production of naked seeds is a distinctive feature of the group of plant called
Answer: B (conifers)
Conifers are gymnosperms: their seeds lie exposed on cone scales instead of inside a fruit.
In which of these features do bryophytes differ from pteridophytes?
Answer: D (Presence of a vascular system.)
Ferns (pteridophytes) have xylem and phloem but mosses (bryophytes) do not. Both lack flowers, show alternation of generations and need water for fertilisation.
Which of the following organs or cell components are common to both the sporophyte and the gametophyte of a fern?
Answer: C (Chloroplasts)
Both the leafy fern plant and the small prothallus are green and make their own food, so both have chloroplasts. Rhizoids belong only to the prothallus; roots and leaves only to the sporophyte.
In which of the following organisms does a single cell perform all the functions of movement, nutrition, growth, excretion and photosynthesis?
Answer: B (Euglena)
Euglena is a single cell that moves with a flagellum and has chloroplasts for photosynthesis. Paramecium and Amoeba cannot photosynthesise, and Spirogyra is a filament of many cells.
In which of the following organisms would glycogen be stored?
Answer: C (Rattus)
Glycogen is the storage carbohydrate of animals; Rattus (the rat) is the only animal listed. Plants and algae store starch.
The most successful group of animals in terms of diversity of species is
Answer: B (arthropoda)
Arthropods, especially insects, have more species than all other animal groups put together.
Flame cells are the
Answer: D (excretory system of flatworms)
Flame cells remove waste and excess water in flatworms such as planaria and tapeworms; they are not used for breathing.
Which of the following is the correct order of the developmental stages?
Answer: D (5 → 3 → 2 → 1 → 4.)
Development starts with the eggs (5), then the young tadpoles (3, 2), the larger tadpole (1) and finally the tadpole with legs (4).
The butterfly is of great economic importance because
Answer: D (it pollinates flowers of crops and other plants.)
As butterflies feed on nectar they carry pollen between flowers, helping crops to set fruit and seed.
Manufactured food in the plant is transported through the
Answer: B (phloem)
Phloem carries sugars made in the leaves to other parts of the plant (translocation); xylem carries water and minerals.
Interveinal chlorosis is normally associated with the deficiency of
Answer: A (magnesium)
Magnesium is part of chlorophyll; when it is lacking, the leaf turns yellow between the veins while the veins stay green.
Osmic acid boiled with a solution of food substance gave a black precipitate. This indicates the presence of
Answer: A (fats and oils)
Osmic acid (osmium tetroxide) turns black with fats and oils, so it is a test for lipids.
Which of the labelled parts is the diastema?
Answer: B (3)
The diastema is the toothless gap between the front teeth and the cheek teeth; label 3 points to this gap.
This lower jaw is typical of a
Answer: A (sheep)
The jaw has front incisors, no canine, a wide gap (diastema) and ridged grinding cheek teeth, the pattern of a herbivore such as the sheep. Dogs and cats have large canines and no diastema.
The end products of the digestion of fats and oils in mammals are
Answer: D (fatty acids and glycerin.)
Lipase breaks fats and oils into fatty acids and glycerol (glycerin).
Blood is pumped into the right ventricle by the contraction of the auricle wall through
Answer: B (3)
Label 3 is at the opening between the right auricle and right ventricle (the tricuspid valve region), through which blood passes when the auricle contracts.
After circulation in the lungs, the blood returns to the left auricle through
Answer: C (5)
Blood coming back from the lungs reaches the left auricle through the pulmonary veins. In the diagram these are the small vessels labelled 5 entering the left side of the heart.
The main function of blood in mammals is to transport
Answer: A (excretory materials from tissues)
Blood carries wastes such as urea and carbon dioxide away from the tissues. The other options have the direction wrong: CO2 goes to the lungs, food goes to the tissues and oxygen comes from the lungs.
Members of the phylum Protozoa use the contractile vacuole
Answer: D (to remove excess water.)
Water keeps entering a freshwater protozoan by osmosis; the contractile vacuole collects it and pumps it out (osmoregulation).
The response shown by the tips of the root and shoot of a plant to the stimulus of gravity is
Answer: D (geotropism.)
A growth response to gravity is geotropism: roots grow down (positive) and shoots grow up (negative).
Which of the following is the correct order of the vertebrae along the spinal column?
Answer: C (Atlas → axis → cervical → thoracic → lumbar → sacral)
From the skull down: atlas, axis, the other cervical vertebrae, then thoracic, lumbar and sacral (followed by caudal).
Which of the following is TRUE of the process of conjugation in Paramecium?
Answer: D (Each micronucleus divides twice.)
During conjugation the macronucleus breaks down while each micronucleus divides twice by meiosis, forming nuclei that are exchanged between the partners.
The bright colours of the comb and feathers in the peacock are for
Answer: C (courtship)
The male peacock displays its bright comb and feathers to attract a female for mating, which is courtship.
The main function of the petal of a flower is to
Answer: A (attract pollination agents)
Brightly coloured, scented petals attract insects and birds that carry pollen. Protecting the bud is the job of the sepals.
In the mammal, the autonomic nervous system consists of
Answer: A (sympathetic and parasympathetic systems)
The autonomic system, which controls involuntary actions, has two parts: sympathetic and parasympathetic.
In H, the cotyledons are carried above the soil because
Answer: B (the hypocotyl grows faster than the epicotyl)
In epigeal germination (H) the hypocotyl lengthens quickly and lifts the cotyledons above the ground.
The function of the structure labelled G is to
Answer: B (protect the young leaves from mechanical damage)
G is the coleoptile, a sheath covering the plumule of a grass seedling; it protects the young leaves as they push through the soil.
When it is cold, the blood vessels of the skin
Answer: B (constrict to reduce the amount of blood flowing to the skin)
In the cold, skin blood vessels narrow (vasoconstriction) so less warm blood reaches the surface and less heat is lost.
Which path does sound entering the human ear follow?
Answer: C (Ear drum → ossicles → oval window)
Sound makes the ear drum vibrate; the ossicles pass and magnify the vibrations to the oval window of the inner ear.
What would happen to a man whose pancreas has been surgically removed?
Answer: A (The level of blood sugar would increase)
Without the pancreas there is no insulin, so glucose is not stored and blood sugar rises (diabetes).
Carnivorous plants are usually found in areas
Answer: A (which are deficient in nitrate)
Insect-eating plants grow in poor soils such as bogs that lack nitrates; they digest insects to get nitrogen.
What is the term used to describe the sum total of biotic and abiotic factors in the environment of the organism?
Answer: C (Ecosystem)
An ecosystem is the living community together with its non-living (abiotic) surroundings, interacting as one unit.
Important abiotic factors which affect all plants and animals in the habitat are
Answer: D (temperature and rainfall)
Temperature and rainfall affect every habitat; turbidity and salinity matter mainly in water, and humidity and wind mainly on land.
The most important physical factor which affects an organism living in the intertidal zone of the seashore is
Answer: C (wave action)
Organisms on the shore between high and low tide are constantly beaten by waves, so they need strong attachment or shells to survive.
At which trophic level would the highest accumulation of a non-biodegradable substance occur?
Answer: B (Tertiary consumers)
Non-biodegradable chemicals such as DDT build up at each step of a food chain (biomagnification), so the top consumers hold the most.
Two organisms of different species, living in close association but not dependent on each other are referred to as
Answer: B (commensals)
In commensalism two species live together; one gains and the other is not harmed, and they do not depend on each other.
Which of the following instruments is NOT used in measuring abiotic factors in any habitat?
Answer: A (Microscope)
A microscope is used to look at small organisms; thermometer, hygrometer and wind vane measure temperature, humidity and wind direction.
Plants adapted for life in salty marsh are called
Answer: C (halophytes)
Halophytes are plants that can live in salty soils or water, such as mangroves.
Which group of plants would be the first colonizers in an ecological succession changing rocks to soil?
Answer: C (Lichens)
Lichens can live on bare rock; they release acids that break the rock down and start soil formation, so they are the pioneers.
Soil fertility can be conserved and renewed by
Answer: B (crop rotation and cover crops)
Rotating crops (including legumes) and keeping a cover crop restores nutrients and protects the soil from erosion.
What ecological condition favours the breeding of black flies?
Answer: D (Fast flowing streams.)
Black-fly (Simulium) larvae attach to rocks in fast-flowing rivers and streams, which is why river blindness is common near rapids.
Carbon monoxide poisons tissues by
Answer: C (combining with haemoglobin)
Carbon monoxide binds to haemoglobin much more strongly than oxygen, so blood cannot carry enough oxygen to the tissues.
Which of the following is an example of discontinuous variation observed in man?
Answer: B (Tongue rolling)
A person either can or cannot roll the tongue, with no in-between, so it is discontinuous. Height, weight and skin colour vary gradually.
In the illustration above, the genotypes of the offsprings are
Answer: B (1 homozygous smooth : 2 heterozygous smooth : 1 wrinkled)
The square gives SS, Ss, sS and ss: one homozygous smooth, two heterozygous smooth (Ss) and one wrinkled (ss).
Cold blooded animals are referred to as
Answer: A (poikilothermic)
Poikilotherms are animals whose body temperature changes with the surroundings, such as lizards and fishes.
Which of the following organisms has lost the pentadactyl limb structure?
Answer: B (Fish)
Bats, frogs and pigeons all have five-digit (pentadactyl) limbs modified for their way of life; fish have fins instead of pentadactyl limbs.