49 questions. Try each one, then open the answer to check yourself and read the explanation.
An association between the root nodule of a leguminous plant and Rhizobium sp, is known as
Answer: D (symbiosis.)
Rhizobium fixes nitrogen for the legume and gets food and shelter in return; both benefit, so it is symbiosis.
Amphibians are normally found
Answer: B (in water and on moist land)
Amphibians breed in water and, as adults, live on moist land where their skin will not dry out.
Viviparity occurs mainly in the
Answer: A (mammals)
Viviparous animals give birth to live young that developed inside the mother, as most mammals do.
The jointed structure in insects that bears organs which are sensitive to touch, smell and vibration is the
Answer: C (antenna)
The jointed antennae carry sense organs for touch, smell and vibration.
Which of the following groups is the most advanced?
Answer: D (Gymnosperms.)
Gymnosperms produce seeds, so they are more advanced than ferns, mosses and thallophytes.
Most monocots are easily recognized by their
Answer: B (long and sword -like leaves)
Typical monocots like grasses and maize have long, narrow, strap- or sword-shaped leaves without petioles.
Water fleas, wood lice and barnacles belong to the group
Answer: B (crustacea)
Water fleas, wood lice and barnacles all have two pairs of antennae and a hard carapace, which places them in the Crustacea.
The mode of feeding in Amoeba and Hydra is
Answer: A (heterotrophic)
Amoeba and Hydra cannot make their own food; they capture and eat other organisms, so they are heterotrophic.
Which of the following organisms does not exist as a single free living cell?
Answer: B (Volvox)
Volvox lives as a hollow colony of many cells; the others are single-celled organisms.
Use the diagram to answer questions 10 and 11. The structures labelled II and III respectively are
Answer: B (male organs and rhizoid)
The diagram is a fern prothallus: the male organs (antheridia, II) lie among the rhizoids (III) on the lower part.
Use the diagram to answer questions 10 and 11. In ferns, the structure above is equivalent to the
Answer: B (gametophyte generation of a moss)
The prothallus carries the sex organs, so it is the gametophyte, like the leafy moss plant.
The centre for learning and memory in the human brain is the
Answer: C (cerebrum)
The cerebrum controls intelligence, learning, memory and voluntary actions.
Urea formation occurs in the
Answer: B (liver)
The liver deaminates excess amino acids and turns the ammonia into urea; the kidneys only remove it.
Use the diagram to answer questions 14 and 15. The structure that holds the yolk in position is labelled
Answer: D (III.)
III is the chalaza, a twisted cord of albumen that holds the yolk in the middle of the egg.
Use the diagram to answer questions 14 and 15. The part labelled IV is the
Answer: B (germinal disc)
IV points to the small spot on the yolk, the germinal disc, from which the chick develops.
The gas produced during tissue respiration can be identified by using
Answer: A (calcium hydroxide)
Carbon (IV) oxide turns lime water (calcium hydroxide solution) milky.
A seedling grown in the dark is likely to be
Answer: A (etiolated)
Without light a seedling grows tall, thin and pale (yellow), which is called etiolation.
The enzyme invertase will hydrolyze sucrose to give
Answer: C (glucose and fructose)
Sucrose is made of one glucose and one fructose unit, which invertase (sucrase) splits apart.
When yeast respires anaerobically, it converts simple sugars to carbon(IV) oxide and
Answer: C (alcohol)
Fermentation by yeast turns glucose into ethanol (alcohol) and carbon (IV) oxide.
The transportation of oxygen and carbon (IV) oxide in mammals is carried out by
Answer: D (erythrocytes.)
Red blood cells (erythrocytes) contain haemoglobin, which carries oxygen and some carbon (IV) oxide.
The veins of the leaf are formed by the
Answer: A (vascular bundles)
Leaf veins are vascular bundles of xylem and phloem that carry water and food.
Use the diagram to answer questions 22 and 23. The parts which function together to bring about hearing are labelled
Answer: C (I, II, III and IV)
Sound passes along the ear canal (I), is carried by the ossicles (II, III) and is detected in the cochlea (IV).
Use the diagram to answer questions 22 and 23. The part labelled II is the
Answer: D (ear ossicles.)
II points to the small bones of the middle ear, the ear ossicles, which pass vibrations to the inner ear.
When specimen X - is mixed with few drops of Iodine solution, the appearance of a blue-black colour confirms that X is
Answer: B (starch)
Iodine turns blue-black with starch.
Use the diagram to answer questions 25 and 26. The structure above respresnts a
Answer: D (cervical vertebra.)
The vertebra has broad, flattened transverse processes with small holes (vertebrarterial canals), which are features of a cervical vertebra.
Use the diagram to answer questions 25 and 26. Blood vessels usually pass through the structure labelled
Answer: C (V)
V is the vertebrarterial canal in the transverse process, through which the vertebral artery and vein pass.
Salts and water are absorbed in the roots and transported to the leaves by
Answer: D (osmosis through the xylem tissues.)
Water enters the root by osmosis and moves up to the leaves in the xylem; phloem carries food, not water and salts.
The number of plant species obtained from a population study of a garden is as follows: Guinea grass (15), Ipomea spp (5), Sida spp (7) and Imperata spp (23). What is the percentage of occurrence of Imperata spp?
Answer: C (46%)
Total = 15 + 5 + 7 + 23 = 50 plants. Imperata = 23/50 × 100 = 46%.
Carbon (IV) oxide content of the atmosphere is least affected by
Answer: D (plant and animal respiration.)
Respiration is part of the balanced carbon cycle, since photosynthesis takes the carbon (IV) oxide back. Deforestation, fires and burning fuels all raise the level.
The factor that least affects food shortages in sub-saharan Africa is
Answer: C (mixed-cropping)
Floods, pests and drought destroy crops, while mixed cropping is a farming practice that actually reduces the risk of crop failure.
The epiphytic habitat can best be described as
Answer: A (arboreal)
Epiphytes grow on the branches of trees, which is an arboreal habitat.
The highest percentage of energy in an ecosystem occurs at the level of the
Answer: C (producers)
Producers capture energy from sunlight, and energy is lost at each step after them, so they hold the most.
The greatest influence on a stable ecosystem in nature is exerted by
Answer: A (man)
Human activities such as farming, building, logging and polluting change ecosystems more than any other factor.
The physical space occupied by an organism together with its functional role in the community can be described as
Answer: C (niche)
A niche is where an organism lives plus the role it plays in the community; habitat is only the place.
A freshwater pond may contain
Answer: C (water lily, fish, water scorpion and dragonfly larva)
Water lily, fish, water scorpion and dragonfly larvae are all common in freshwater ponds; sharks, crabs and shrimps are mainly marine.
The hygrometer is used for measuring
Answer: A (relative humidity)
A hygrometer measures the relative humidity of the air.
The distribution of plants in a rain forest is governed mainly by
Answer: C (amount of sunlight)
Within a rain forest, plants are arranged in layers according to how much sunlight reaches each level, from tall emergents to shade plants on the floor.
Both recessive and dominant characters are found
Answer: B (at the same locus of a homologous chromosome)
Dominant and recessive alleles of a gene occupy the same position (locus) on a pair of homologous chromosomes.
The probability of a baby being a boy or a girl depends on the contribution of the
Answer: A (father's sex cell)
Every egg carries an X; the sperm carries either X (girl) or Y (boy), so the father's sex cell decides.
Which of the following statements is true of blood groups and blood transfusion?
Answer: C (group AB is the universal recipient)
Group AB blood has no anti-A or anti-B antibodies, so it can receive blood of any group.
A tall plant crossed with a dwarf one produces offspring of which half are tall and half are dwarf. What are the genotypes of the parents?
Answer: B (Tt, tt)
Tt × tt gives Tt and tt in equal numbers, so half are tall and half dwarf.
In man, the ability to roll the tongue is a variation classified as
Answer: B (physiological)
Tongue rolling is something the body can or cannot do, not a visible shape, so it is a physiological variation.
Darwin is considered the first scientist who correctly explained the theory of
Answer: D (organic evolution.)
Darwin explained organic evolution through natural selection; use and disuse was Lamarck's idea.
The stem of a typical aquatic plant usually has many
Answer: A (air cavities)
Air cavities (aerenchyma) keep aquatic plants afloat and store air for respiration.
The role of the male adult honey bee is to
Answer: C (mate with the queen)
Male bees (drones) do no work in the hive; their only job is to mate with the queen.
The ability of an organism to live successfully in an environment is known as
Answer: D (adaptation.)
Adaptation is having features that let an organism survive and reproduce in its environment.
The most important adaptation of xerophytes is the ability of the protoplasm to
Answer: A (resist being damaged by loss of water)
Xerophyte protoplasm can lose a lot of water without being damaged, letting the plant survive long droughts.
A green snake in green grass is able to escape notice from predators because of its
Answer: D (cryptic colouration.)
The snake's colour matches the grass so it blends in and is hard to see, which is cryptic colouration (camouflage).
For heterotrophic organisms, competition is least caused by the inadequacy of
Answer: C (light)
Heterotrophs do not need light to make food, so they rarely compete for it; they compete for food, space and mates.