49 questions. Try each one, then open the answer to check yourself and read the explanation.
The organelle common to both plant and animal cells is the
Answer: B (plasmalemma)
The plasmalemma (cell membrane) surrounds every cell, plant or animal. Cell walls and chloroplasts are found only in plants, and centrioles mainly in animal cells.
Which of the following is likely to have a higher concentration of mitochondria?
Answer: A (Sperm cell)
A sperm swims actively and needs a lot of energy, so its middle piece is packed with mitochondria. Mature red blood cells have no mitochondria at all.
The hyphal wall of fungi is rigid owing to the presence of
Answer: D (chitin)
Fungal cell walls are made mainly of chitin, a tough substance also found in insect skeletons. Plant walls use cellulose and lignin.
Angiosperms and gymnosperms belong to the class
Answer: B (spermatophyta)
Both angiosperms and gymnosperms reproduce by seeds, so they are grouped as spermatophytes (seed plants).
An example of a radially symmetrical organism is
Answer: B (Hydra)
Hydra is a coelenterate with its body parts arranged in a circle around a central axis. Planaria, tapeworms and roundworms are bilaterally symmetrical.
The leech and the earthworm belong to the
Answer: D (annelids)
Leeches and earthworms have soft bodies divided into ring-like segments. They are annelids (segmented worms).
I. Rattus rattus II. Agama agama III. Bufo regularis IV. Tilapia zilli
The order of evolutionary advancement of the above vertebrates is
Answer: D (IV, III, II, I)
Tilapia is a fish, Bufo a toad (amphibian), Agama a lizard (reptile) and Rattus a rat (mammal). From least to most advanced: fish, amphibian, reptile, mammal = IV, III, II, I.
Use the diagram of the plant to answer: The angle between the parts labelled II and III is the
Answer: D (axil)
II is the stem and III is a leaf. The upper angle between a leaf and the stem is called the axil, where buds form.
Use the diagram of the plant to answer: The part of the plant where photosynthesis is least likely to take place is
Answer: D (IV)
IV is the root, which is under the soil with no light and no chlorophyll. Photosynthesis cannot take place there.
The stage in the life history of a moth responsible for the destruction of agricultural crops is the
Answer: D (caterpillar)
The caterpillar (larva) feeds heavily on leaves and other plant parts. The adult moth only sips nectar and the pupa does not feed.
The blackfly is a vector of
Answer: C (onchocerciasis)
Blackflies (Simulium) carry the worm that causes onchocerciasis (river blindness). Malaria and yellow fever are spread by mosquitoes, and sleeping sickness by tsetse flies.
The transition from amphibians to mammals involves the limbs becoming arranged to support the weight more effectively requiring modifications in the
Answer: B (pectoral and pelvic girdles)
The limbs are attached to the body by the pectoral (shoulder) and pelvic (hip) girdles. These had to change so the legs could hold the body up off the ground.
The main function of the caudal fin in Tilapia is to
Answer: A (propel it forward in water)
The tail (caudal) fin is swept from side to side to push the fish forward. Other fins mainly steer and balance.
In the root vascular system, the stele is directly surrounded by the
Answer: C (endodermis)
The endodermis is a ring of cells wrapped directly around the stele. The pericycle is the outer layer of the stele itself, and the cortex lies outside the endodermis.
Use the diagram of the digestive organs to answer: The part labelled IV represents the
Answer: D (duodenum)
IV is the first part of the small intestine leaving the stomach, next to the pancreas. That is the duodenum.
Use the diagram of the digestive organs to answer: The bile is stored in the part labelled
Answer: B (II)
II points to the gall bladder on the underside of the liver. Bile made by the liver is stored there.
The only vein that carries pure oxygenated blood is the
Answer: B (pulmonary vein)
The pulmonary vein brings blood from the lungs, where it picked up oxygen, back to the heart. All other veins carry deoxygenated blood.
The function of the fluid-filled pericadium is to
Answer: A (reduce the friction caused by the pumping movements of the heart)
The fluid between the layers of the pericardium works like a lubricant. It lets the heart beat without rubbing against the surrounding tissues.
The mammalian lung is made airtight by the
Answer: C (pleural membrane)
The pleural membranes line the lungs and the chest wall and seal the chest cavity. This airtight seal is what lets the lungs fill when the chest expands.
A test tube containing yeast in glucose solution was suspended in a covered conical flask containing alkaline pyrogallol. The bubbles of carbon (IV) oxide produced indicate that the yeast cells are
Answer: A (respiring in the absence of oxygen)
Alkaline pyrogallol absorbs oxygen, so the yeast has no oxygen. Bubbles of carbon(IV) oxide show it is still respiring anaerobically (fermentation).
The urinary tubules of the kidney function through
Answer: C (ultrafiltration and selective reabsorption)
Blood is filtered under pressure in the Bowman's capsule (ultrafiltration). Useful substances are then taken back into the blood along the tubule (selective reabsorption).
Excess water in plants is excreted as water vapour and droplets respectively through
Answer: B (transpiration and guttation)
Plants lose water vapour through their stomata in transpiration. Guttation pushes out liquid droplets through pores at the leaf edges.
When bacteria swim from cold to warm regions, this is known as
Answer: B (positive thermotaxis)
Taxis is movement of a whole organism in response to a stimulus. Moving towards warmth is positive thermotaxis.
Hydrostatic skeleton is the type of supporting system found in
Answer: C (oligochaetes)
Earthworms (oligochaetes) are supported by fluid under pressure in their body cavity. Mammals and reptiles have bony skeletons and arthropods have exoskeletons.
Use the diagram of the male urinogenital system to answer: The structure labelled I originates from the
Answer: B (kidney)
I is the ureter, the tube that carries urine down to the bladder. It starts from the kidney.
Use the diagram of the male urinogenital system to answer: Birth control by vasectomy is achieved by severing the structure labelled
Answer: C (III)
In a vasectomy the sperm ducts (vas deferens) are cut so sperm cannot reach the semen. III is the sperm duct.
Use the diagram of the germinating seed to answer: The type of germination illustrated is termed
Answer: C (epigeal)
The diagram shows the cotyledons being carried above the soil level. This is epigeal germination.
Use the diagram of the ear to answer: The structure labelled I is the
Answer: D (stapes)
I points to the innermost ear ossicle, which fits into the oval window. That bone is the stapes (stirrup).
Use the diagram of the ear to answer: A function of the part labelled II is to
Answer: A (equalize pressure on both sides of the tympanum)
II is the Eustachian tube, which links the middle ear to the throat. It lets air in or out so the pressure is the same on both sides of the eardrum.
Which of the following is a homeostatic response in humans?
Answer: D (Shivering in a cold environment)
Shivering makes the muscles produce heat when the body is cold. This keeps body temperature steady, which is homeostasis.
Use the graph to answer: The optimal temperature for breeding cockroaches is
Answer: C (24°C)
The best temperature is the one where the population grows fastest and biggest. On the graph, the 24°C curve rises highest, to about 500.
Use the graph to answer: At which temperature will cockroaches not survive after 10 days.
Answer: A (15°C)
Find the curve that drops to zero. The 15°C population peaks at about 7 days and then falls to zero at about 10 days, so cockroaches kept at 15°C do not survive after 10 days.
Use the water cycle diagram to answer: Evaporation and transpiration are respectively represented by the components labelled
Answer: A (I and II)
I shows water rising into the atmosphere from the ground and the ocean (evaporation). II shows water rising from the plant (transpiration).
Use the water cycle diagram to answer: The main reservoir of water in the cycle is the
Answer: D (ocean)
About 97% of the Earth's water is in the oceans. Clouds, groundwater and plants hold far less.
The Mambilla plateau is a unique Nigerian biome located in
Answer: C (Taraba State)
The Mambilla plateau, with its cool montane grassland, is in Taraba State near the Cameroon border.
In Nigeria, the Guinea savanna belt borders the
Answer: B (rainforests and the Sudan savanna)
Going north, the order is rain forest, Guinea savanna, then Sudan savanna. So the Guinea savanna lies between the rain forest and the Sudan savanna.
The population density of Tridax in an abandoned square farmland of side 200 m was found to be 5 plants per m2. The population size of the plant on the farm is
Answer: D (200 000)
Area = 200 m × 200 m = 40 000 m². Population = 5 × 40 000 = 200 000 plants.
Secondary succession is much faster than primary succession because
Answer: B (Soil is already present)
Secondary succession starts on land that already has soil, seeds and nutrients, for example after a fire. Primary succession must first make soil from bare rock, which takes a long time.
Which of the following is used to test for the presence of lime in a soil sample?
Answer: C (HCl(aq))
Lime (calcium carbonate) fizzes, giving off carbon(IV) oxide, when dilute hydrochloric acid is added. Sodium hydroxide is an alkali and gives no fizzing.
The importance of practising crop rotation in agriculture is to
Answer: A (maintain soil fertility)
Different crops use different nutrients, and legumes add nitrogen. Rotating crops stops one set of nutrients from being used up, keeping the soil fertile.
The recycling method of solid waste disposal is unsuitable for
Answer: A (organic matter)
Glass, plastics and metals can be melted and remade into new products. Organic matter rots and is better composted than recycled.
A non-renewable alternative source of energy is
Answer: C (nuclear energy)
Nuclear energy uses uranium, which is mined and gets used up. Wind, sunlight and flowing water are renewed naturally.
Which of the following is the best explanation for a child who is phenotypically short and born of two tall parents?
Answer: D (Both parents possess genes for shortness)
Shortness here is recessive, so the child must have two short alleles (tt). Each parent must be Tt, carrying one gene for shortness.
A yellow maize is crossed with a white maize and the first filial generation produce yellow maize only. The white trait is said to exhibit
Answer: B (recessiveness)
The white trait disappears in the F1 because the yellow allele masks it. A trait that is hidden in this way is recessive.
The association in which one member benefits and the other is relatively unaffected by the interraction is termed
Answer: C (commensalism)
In commensalism one partner gains and the other is neither helped nor harmed. In parasitism the host is harmed, and in mutualism both gain.
When a peacock displays its colourful feathers, it is
Answer: D (courting a female)
The male peacock spreads his bright tail feathers to attract a female for mating. This is courtship behaviour.
When an animal has a dark-coloured dorsal surface and a light-coloured ventral surface, this is an adaptation called
Answer: B (countershading)
A dark back and pale belly cancel out the shadows made by light from above. The animal looks flat and is harder to see. This is countershading.
The only caste in the termite colony whose members can feed themselves are the
Answer: B (workers)
Workers collect and digest food and feed the queen, king, soldiers and young. The soldiers' huge jaws stop them from feeding themselves.
An evidence of a common ancestry for fishes, amphibians, reptiles, birds and mammals is the
Answer: C (presence of gill clefts in vertebrate embryos)
All vertebrate embryos have gill clefts at an early stage. This shared feature suggests they came from a common fish-like ancestor.