47 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 structure labelled I is the
Answer: C (endoplasmic reticulum)
Part I points to the network of membranes running through the cytoplasm, which is the endoplasmic reticulum.
Use the diagram to answer questions 1 and 2. Protein is synthesized in the part labelled
Answer: A (I)
Proteins are made on ribosomes, many of which sit on the rough endoplasmic reticulum (part I).
Which of the following is the youngest plant tissue?
Answer: A (Meristem)
Meristem is made of newly formed, actively dividing cells; all other tissues develop from it.
Viruses differ from all forms of life because they
Answer: D (reqiure other living cells to multiply.)
Viruses cannot reproduce on their own; they can only multiply inside living host cells.
The cnidoblast cells found in hydra are used for
Answer: B (offence and defence)
Cnidoblasts contain stinging threads (nematocysts) that paralyse prey and drive off enemies, so they serve offence and defence.
Annelids differ from nematodes in that they
Answer: C (are metamerically segmented)
Both groups are bilateral, triploblastic and have a complete gut, but only annelids have a body divided into repeated segments (metameric segmentation).
Which of the following perform similar functions?
Answer: D (Strobili and inflorescence.)
A strobilus (cone) carries spore-bearing structures and an inflorescence carries flowers, so both do the same job of bearing reproductive organs.
In ferns, the sporophyte
Answer: D (is diploid and independent of the gametophyte.)
The fern plant we see is the sporophyte: it is diploid and, once established, lives independently of the small gametophyte (prothallus).
The group of insects that undergoes complete metamorphosis is
Answer: C (houseflies, beetles and butterflies)
Houseflies, beetles and butterflies all pass through egg, larva, pupa and adult; cockroaches, grasshoppers and aphids have incomplete metamorphosis.
The nitrogenous substance that is excreted by birds in order to conserve water is
Answer: C (uric acid)
Uric acid is almost insoluble, so birds can excrete it as a paste with very little water.
In mammals, the exchange of nutrients and metabolic products occurs in the
Answer: A (lymph)
Cells exchange nutrients and wastes with the blood through the tissue fluid (lymph) that bathes them.
The part of the stomach nearer the gullet is called the
Answer: B (cardiac sphincter)
The cardiac sphincter guards the entrance of the stomach from the gullet; the pyloric sphincter is at the exit to the duodenum.
Trace elements are required by plants mainly for the
Answer: A (formation of pigments and enzymes)
Trace elements such as iron, copper, zinc and manganese are needed in tiny amounts, mainly as parts of pigments and enzymes.
Use the diagram to answer questions 14 and 15. The parts labelled I and II constitute the
Answer: A (crown)
Parts I and II are at the top of the tooth, above the gum, which is the crown.
A food substance was treated with a few drops of Sudan III solution and a red coloration was obtained. The food contained
Answer: C (fat)
Sudan III stains fats and oils red, so a red colour shows fat is present.
Oozing out of water from the leaves of plants in a humid environment is known as
Answer: D (guttation)
Guttation is the loss of liquid water droplets through hydathodes at leaf edges, common when the air is humid.
The element that is essential for the coagulation of blood is
Answer: B (calcium)
Calcium ions are needed for the conversion of prothrombin to thrombin during clotting.
Anaerobic respiration differs from aerobic respiration by the production of
Answer: C (less amount of energy and alcohol)
Anaerobic respiration (e.g. in yeast) releases much less energy than aerobic respiration and produces alcohol instead of water.
Stomatal pores open when there is
Answer: A (an increase in the sugar content of guard cellls)
More sugar in the guard cells draws in water by osmosis; they swell, curve apart and the pore opens.
The process of deamination is essential for the
Answer: C (formation of urea)
In deamination the liver removes the amino group from excess amino acids and turns it into urea.
A band of connective tissue linking two bones in a joint is known as
Answer: D (ligament.)
Ligaments join bone to bone; tendons join muscle to bone.
The appendicular skeleton is composed of the pectoral girdle
Answer: A (pelvic girdle, fore and hind limbs)
The appendicular skeleton is the girdles and the limbs attached to them; vertebrae belong to the axial skeleton.
The companion cells are part of the
Answer: B (phloem)
Companion cells lie beside the sieve tubes in phloem and keep them working.
In which of the following groups of vertebrates would the largest amount of yolk be found in the egg?
Answer: D (Reptiles.)
Reptile eggs develop on land with no larval stage, so they carry a large yolk store; mammal embryos are fed through the placenta.
Use the diagram to answer questions 26 and 27. The function of the part labelled V is for the passage of
Answer: A (pollen tube and pollen nucleus)
V is the micropyle, the opening through which the pollen tube carrying the male nuclei enters the ovule.
Use the diagram to answer questions 26 and 27. The female gamete is represented by
Answer: D (IV.)
The female gamete is the egg cell. It lies in the embryo sac at the micropyle end, the end where the pollen tube enters, so it is the cell labelled IV.
The type of vegetative reproduction illustrated in the diagram above is
Answer: B (adventitious bud)
The leaf (as in Bryophyllum) has buds growing from its edges that form new plants, which is propagation by adventitious buds.
Coconut and oil palm fruits can be grouped as
Answer: D (drupe.)
Both have a hard stony endocarp around the seed, which makes them drupes.
The substance that is responsible for apical dominance in plants is known as
Answer: C (auxin)
Auxin made in the shoot tip suppresses the growth of side buds, which is apical dominance.
The part of the brain that regulates most biological cycles in humans is
Answer: D (pineal body.)
The pineal body releases melatonin in response to light and dark, setting the body's biological rhythms such as the sleep cycle.
The ability of the eye to focus on both near and distant objects is termed
Answer: D (accommodation.)
Accommodation is the change in lens shape that lets the eye focus at different distances.
The speed of wind can be measured with an instrument called
Answer: C (anemometer)
An anemometer measures wind speed; a wind vane only shows its direction.
Which organism in the food -web illustrated above is an omnivore?
Answer: B (Rat)
The rat feeds on both a plant (rice) and an animal (weevils), so it is an omnivore.
Toads and lizards in an ecosystem depend on a limited quantity of food. This is an example of
Answer: D (interspecific competition.)
Toads and lizards are different species, so competition between them for the same food is interspecific.
Adaptive features of plants to desert conditions include
Answer: A (thick barks, succulent stems and sunken stomata)
Thick bark reduces water loss, succulent stems store water and sunken stomata cut transpiration.
The Southern Guinea Savanna differs from the Northern Guinea Savanna in that it has
Answer: C (more rainfall and taller grasses)
The southern belt is nearer the forest, so it receives more rain and supports taller grasses.
After a heavy rainfall and the formation of a large pond, the most likely sequence of changes in the vegetation of the pond is
Answer: D (Euglena ← Spirogyra ← water lily ← grass.)
Simple microscopic algae colonise first, then filamentous algae, then rooted floating plants like water lily, and finally land plants such as grass as the pond silts up.
In a soil sample, the relative amounts of the different soil particles can best be determined by the process of
Answer: D (sedimentation.)
Shaking soil in water and letting it settle separates gravel, sand, silt and clay into layers whose thickness can be compared.
Which is the most important pollutant of marine environment in Nigeria?
Answer: C (Oil)
Nigeria's oil industry is offshore and in the Niger Delta, so oil spills are the biggest pollution threat to its marine environment.
One of the most effective ways of controlling guinea worm is by
Answer: D (provision of portable drinking water.)
Guinea worm is caught by drinking water containing infected water fleas, so safe (potable) drinking water stops its spread.
During binary fission in lower organisms, the nucleus is known to undergo
Answer: A (mitosis)
Binary fission produces two identical daughter cells, so the nucleus divides by mitosis.
One reason for the success of Mendel's work is that the
Answer: B (introduced quantitative and qualitative elements into his work)
Mendel counted his pea offspring and analysed the ratios mathematically, adding quantitative analysis to describing traits.
The homozygous condition HbSHbS results in sickle cell anaemia whereas HbA HbS has the sickling trait. What is the probability that a couple with the sickling trait will give birth to one normal child?
Answer: B (1/4)
HbAHbS × HbAHbS gives AA : AS : SS in the ratio 1 : 2 : 1, so the chance of a normal (AA) child is 1/4.
Water loss is regulated in plants and animals by both the
Answer: D (leathery cuticle and the feathers.)
A thick, leathery cuticle cuts water loss from plant surfaces, and feathers cover a bird's skin and reduce evaporation.
What combination of characters should a prey develop to survive in the environment of its predator?
Answer: A (Camouflage, well developed limbs and effective vision)
Camouflage hides the prey, good vision spots the predator early and strong limbs help it escape.
The three classes in a termitarium are
Answer: B (workers, soldiers and reproductives)
A termite colony has three castes: workers, soldiers and reproductives (the king and queen).
Long neck in giraffe is used to illustrate the theory of
Answer: A (use and disuse)
Lamarck explained the giraffe's long neck by stretching to reach leaves, his theory of use and disuse.