45 questions. Try each one, then open the answer to check yourself and read the explanation.
Which of the following organisms contains chlorophyll in its cells?
Answer: C (Euglena.)
Euglena has chloroplasts and can photosynthesise; caterpillars, grasshoppers and Paramecium cannot.
Species are groups of organisms that
Answer: C (have similar features and can interbreed freely.)
Members of one species look alike and can interbreed to produce fertile offspring.
A plant with short, vertical underground stem is a
Answer: B (corm.)
A corm (e.g. cocoyam) is a short, swollen, vertical underground stem. A rhizome grows horizontally.
The diagram below is an illustration of a reproductive process in an organism. The type of reproduction illustrated is
Answer: B (binary fission.)
The single-celled organism splits across the middle into two equal daughter cells, which is binary fission.
The diagram below is an illustration of a reproductive process in an organism. The illustrated organism is capable of reproducing by
Answer: D (sexual and asexual means.)
The organism is Paramecium. It reproduces asexually by binary fission (as shown) and also sexually by conjugation, so it uses both means.
Which of the following organisms consists of unicellular cells joined to form a filament?
Answer: B (Spirogyra)
Spirogyra is a green alga made of cells joined end to end in an unbranched filament; the others are single free cells.
The bursting of a red blood cell placed in a hypotonic solution is called
Answer: B (haemolysis.)
In a hypotonic solution water enters the red cell by osmosis until it bursts; the bursting of red cells is haemolysis. Crenation is shrinking in a hypertonic solution.
The function of the root hair in plants is to
Answer: A (absorb soil water by the process of osmosis.)
Root hairs give a large surface for taking in water from the soil by osmosis (and mineral salts).
The lumbar vertebra differs from the thoracic vertebra because it possesses a
Answer: C (thicker centrum.)
Lumbar vertebrae carry the most body weight, so they have large, thick centra. Thoracic vertebrae have the long neural spines.
The structures that contain grey matter and white matter are found in the
Answer: B (nervous system.)
Grey matter (cell bodies) and white matter (nerve fibres) make up the brain and spinal cord, which belong to the nervous system.
The diagram below is an illustration of a sense organ in humans. The part that protects the organ is labeled
Answer: B (II.)
II points to the eyelashes and eyelid, which shield the eye from dust and injury.
The diagram below is an illustration of a sense organ in humans. The part labeled III is the
Answer: B (pupil.)
III points to the dark central opening through which light enters the eye: the pupil.
The diagram below is an illustration of two plants P and Q. Arrows I, II and III illustrate the transfer of pollen grains among flowers of plants P and Q. The types of pollination illustrated as I, II and III, respectively are
Answer: B (self, self and cross.)
I and II move pollen between flowers of the same plant P, which is self-pollination. III carries pollen from plant P to plant Q, which is cross-pollination.
The diagram below is an illustration of two plants P and Q. Arrows I, II and III illustrate the transfer of pollen grains among flowers of plants P and Q. The condition necessary for reproduction to occur between plants P and Q after pollination is that plants P and Q should be
Answer: A (of the same species.)
Pollen can only fertilise ovules of a plant of the same species, so P and Q must be one species.
The diagram below illustrates a dry dehiscent fruit. The agent of dispersal of the fruit is
Answer: D (wind.)
The fruit carries a light, feathery parachute of hairs that lets the wind carry it.
The diagram below illustrates a dry dehiscent fruit. The parachute-like tuft of hairs developed from the
Answer: D (sepals.)
The pappus (tuft of hairs) of fruits such as Tridax and sunflower family members is a modified calyx, i.e. the sepals.
Which of the following events does not occur in the light reaction stage of photosynthesis?
Answer: B (Carbon (IV) oxide combines with hydrogen)
Carbon (IV) oxide is reduced by hydrogen in the dark (light-independent) stage. Light absorption and splitting of water happen in the light stage.
The rate of photosynthesis decreases in a wilted herbaceous plant because the
Answer: D (amount of carbon dioxide entering to the leaf decreased.)
When a plant wilts its guard cells lose water and the stomata close, so less carbon dioxide enters the leaf.
The element required for chlorophyll formation in plants is
Answer: A (iron.)
Iron is needed by the enzymes that make chlorophyll, so lack of iron causes yellow leaves (chlorosis). Magnesium, which is part of the chlorophyll molecule, is not among the options.
The process of food digestion in mammal would
Answer: D (render food substances soluble and absorbable.)
Digestion breaks large insoluble food molecules into small soluble ones that can be absorbed into the blood.
Which of the following food substances would give a negative reaction with Benedict's reagent?
Answer: D (Sucrose)
Sucrose is a non-reducing sugar, so it does not turn Benedict's solution brick-red; glucose, fructose and galactose are reducing sugars.
Sunlight is the major source of
Answer: A (Vitamin D.)
The skin makes vitamin D when it is exposed to sunlight.
Discouraging the use of poison to kill fish in a large water body is a way of
Answer: B (conserving the fish species.)
Poison kills all fish, young and old, and pollutes the water; banning it protects (conserves) the fish.
The illustration below is a food chain: Grasses → Grasshoppers → Lizards → Hawks. Which of the following statements is not correct about the food chain? The number of
Answer: B (grasses eaten by grasshoppers is fewer than the number of grasshoppers.)
Each consumer eats many organisms from the level below, so the grasses eaten are more than the grasshoppers. Statement B says the opposite, so it is the incorrect one.
The illustration below is a food chain: Grasses → Grasshoppers → Lizards → Hawks. If the individual species of organisms in the food chain are counted and arranged as a pyramid, the result would be a pyramid of
Answer: A (numbers.)
Counting the individuals at each feeding level gives a pyramid of numbers.
Which of the following gases is released during the decomposition of organic matter?
Answer: C (Hydrogen sulphide)
When proteins in dead matter rot, their sulphur is released as hydrogen sulphide, the gas that gives decay its rotten-egg smell. Carbon (II) oxide comes from incomplete burning, not decay.
The diagrams below are illustrations of organisms from different habitats. The structures labelled I are for
Answer: C (physical defence.)
I points to the snail's hard shell and the spines of the other organism; both protect the organism physically from attack.
The diagrams below are illustrations of organisms from different habitats. Habitats of the organisms respectively, are
Answer: D (garden and desert.)
The first organism is a land snail, common in gardens, and the second is a spiny cactus, a plant of deserts.
An environmental problem caused by sulphur (IV) oxide is
Answer: A (acid rain.)
Sulphur (IV) oxide dissolves in rain water to form acids, which fall as acid rain.
The phenomenon by which a farmland that is left to fallow for several years develops into a forest is called
Answer: A (succession.)
The gradual replacement of one plant community by another until a forest (climax) forms is ecological succession.
A farmer planted many seeds on a small piece of land. The plants that germinated are as shown below.
Which of the following effects would not be observed among the population of the plants?
Answer: C (Mutualistic relationship.)
Overcrowding causes competition for light, water and nutrients, faster spread of disease and death of weak plants. It does not create mutualism.
The bar chart below shows the data of sources of energy used for cooking in a community. The source of energy that is mostly used in the community is
Answer: B (kerosene.)
Kerosene has the tallest bar (6 households), more than any other source.
The bar chart below shows the data of sources of energy used for cooking in a community. The two sources of energy that would mostly lead to pollution in the community are
Answer: C (kerosene and coal.)
Burning kerosene and coal releases smoke, soot and harmful gases; solar and wind energy are clean.
An individual found a strange bird that is tagged as an endangered specie. What should the individual do?
Answer: C (Return it to its natural habitat.)
An endangered animal should be protected, so it should be returned to its natural habitat where it can survive and breed.
The diagram below is an illustration of the genetic cross between two parents. The parental gametes I, II, III and IV gave rise to the offspring below. Gametes I, II, III and IV, respectively are
Answer: B (T, t, t and t.)
I and III give Tt while II and III give tt, so III is t, I is T and II is t. I and IV give Tt, so IV is also t.
The physical appearance of an organism is described as its
Answer: A (phenotype.)
Phenotype is the observable characteristics of an organism; genotype is its genetic make-up.
The male and female gametes which bear genes for inheritance in plants are located in the
Answer: C (stamens and pistils.)
Male gametes form in pollen in the stamens; female gametes (egg cells) are in the ovules in the pistil.
Which type of breeding is represented by industrial melanism in peppered moths?
Answer: B (Natural selection.)
In soot-darkened areas dark moths were hidden from birds and survived to breed more; this is natural selection.
In a test, a student paired some scientists with their famous work as shown below.
I. Charles Darwin → preservation of some food with heat
II. Gregor Mendel → natural selection
III. Jean Baptiste Lamarck → inheritance of acquired characteristics
IV. Louis Pasteur → independent assortment of genes
The scientists that are not correctly paired with their famous works are
Answer: C (I, II and IV.)
Darwin proposed natural selection, Mendel independent assortment, and Pasteur food preservation by heat. Only Lamarck (III) is correctly paired.
In a test, a student paired some scientists with their famous work as shown below.
I. Charles Darwin → preservation of some food with heat
II. Gregor Mendel → natural selection
III. Jean Baptiste Lamarck → inheritance of acquired characteristics
IV. Louis Pasteur → independent assortment of genes
Which of the scientists were involved in the study of evolution?
Answer: A (I and III)
Darwin (natural selection) and Lamarck (use and disuse, inheritance of acquired characters) both put forward theories of evolution.
Section A
(a) State one function each of the following parts of the nephron: (i) glomerulus; (ii) Bowman's capsule; (iii) Proximal convoluted tubule; (iv) distal convoluted tubule.
(b) Complete the table below:
Table columns: Organism | Structure for excretion | Form in which waste is excreted by organism
Rows: ______ | Contractile vacuole | ______
Flatworm | ______ | ______
Earthworm | ______ | ______
Cockroach | ______ | ______
Human | ______ | Liquid
______ | Stomatal pore | ______
(c) List five excretory products of plants.
(a)(i) Glomerulus: ultrafiltration of blood under high pressure.
(ii) Bowman's capsule: collects the glomerular filtrate and passes it into the tubule.
(iii) Proximal convoluted tubule: selective reabsorption of glucose, amino acids, salts, vitamins and much water.
(iv) Distal convoluted tubule: reabsorbs more water and salts (osmoregulation) and secretes some ions (e.g. H+, K+) into the urine.
(b) Amoeba/Paramecium - contractile vacuole - liquid (and gases by diffusion);
Flatworm - flame cells - liquid;
Earthworm - nephridia - liquid;
Cockroach - Malpighian tubules - solid (uric acid);
Human - kidney (also skin, lungs) - liquid (urine);
Green plant - stomatal pore - gas (carbon (IV) oxide, oxygen, water vapour).
(c) Any five: oxygen; carbon (IV) oxide; water; tannins; resins; gums; latex; alkaloids (e.g. quinine, caffeine, nicotine, morphine); oxalic acid / calcium oxalate crystals; anthocyanins.
In (b), fill every blank: the organism, its excretory structure and the state of its waste.
An individual ate a hot and large meal of cassava with salty groundnut soup. The individual was sweating profusely and did not drink water after the meal.
(a) State one role each played by the following organs involved in the activity above: (i) mouth; (ii) skin; (iii) tongue; (iv) kidney; (v) stomach; (vi) small intestine; (vii) large intestine; (viii) liver.
(b) Name three of the organs listed in 2(a) that contain enzymes needed to breakdown the food.
(c) Name three digestive enzymes that would be involved in the digestion of the meal.
(d) Name two end products of the meal after digestion.
(e)(i) State one effect that the excess salt in the meal might have on the individual. (ii) State three advantages that the individual would derive from the meal.
(a)(i) Mouth: teeth chew the food; saliva (ptyalin) begins starch digestion.
(ii) Skin: sweat glands remove water and salt and cool the body.
(iii) Tongue: tastes the food and rolls it into a bolus for swallowing.
(iv) Kidney: removes excess salt and conserves water (osmoregulation), producing concentrated urine.
(v) Stomach: stores and churns food; pepsin starts protein digestion; acid kills germs.
(vi) Small intestine: completes digestion of starch, proteins and fats and absorbs the products through the villi.
(vii) Large intestine: absorbs water from undigested food and forms faeces.
(viii) Liver: makes bile to emulsify fats; stores excess glucose as glycogen; deaminates excess amino acids.
(b) Mouth, stomach, small intestine (also accept pancreas/duodenum if listed).
(c) Any three: salivary amylase (ptyalin); pancreatic amylase; maltase; pepsin; trypsin; erepsin (peptidase); lipase.
(d) Any two: glucose; amino acids; fatty acids and glycerol.
(e)(i) Any one: raised blood pressure; thirst and dehydration; strain on the kidneys; water retention/swelling.
(ii) Any three: energy from the cassava (carbohydrate); protein from groundnut for growth and repair; oil (fat) from the soup for energy and warmth; minerals and vitamins.
Link each organ's role to this salty, starchy meal and the lack of drinking water.
(a) A piece of raw meat was left in an uncovered bowl for seven days.
Use the information to answer questions 3(a) and 3(b).
(i) State four likely changes that would be observed in the meat.
(ii) Name the biological process that led to the changes that are observed in the meat.
(iii) On the table below, list four methods of preserving meat to prevent it from the changes stated in 3(a)(i) and mention the principle involved in the methods.
Table columns: Four methods of preserving the meat | One principle involved in the preservation method
(iv) Name two environmental factors that may be responsible for the changes in 3(a)(i).
(b) Name one method of preserving the following food items: (i) dried maize grains; (ii) fresh tomatoes; (iii) vegetables; (iv) beans; (v) milk.
(a)(i) Any four: bad (offensive) smell; change of colour (greenish/dark); soft, slimy texture; presence of maggots; growth of moulds/microbes; liquid oozing out.
(ii) Decay (putrefaction / decomposition by bacteria and fungi).
(iii) Any four with principle: refrigeration/freezing - low temperature slows microbial growth and enzymes; drying/smoking - removes water microbes need; salting - draws water out of microbes by osmosis; canning - heat kills microbes and the sealed can keeps new ones out; cooking/boiling - heat kills microbes.
(iv) Any two: warm temperature; moisture/humidity; oxygen (air); presence of microorganisms/flies.
(b)(i) Dried maize grains: sun-drying and storing in airtight containers/silos with chemicals.
(ii) Fresh tomatoes: refrigeration (or canning as paste, drying).
(iii) Vegetables: refrigeration or drying.
(iv) Beans: drying and storage in airtight containers/with preservatives.
(v) Milk: pasteurisation, refrigeration, or drying into powder.
Each preservation method must be paired with its own principle.
(a)(i) Complete the table below by stating the type of cell division and the type of set of chromosomes for the listed cells.
Table columns: Cell | Types of cell division | Set of chromosomes
Rows: Onion cell | mitosis | ______; Sperm cell; Pollen grain; Ovum; Guard cell; Cheek cell | ______ | diploid
(ii) What is mitosis?
(b) Explain briefly how parents with blood groups A or B could have an offspring with blood group O.
(c) Explain briefly how genes are involved in the process of evolution.
(a)(i) Onion cell - mitosis - diploid; Sperm cell - meiosis - haploid; Pollen grain - meiosis - haploid; Ovum - meiosis - haploid; Guard cell - mitosis - diploid; Cheek cell - mitosis - diploid.
(ii) Mitosis is cell division in which one cell divides to give two daughter cells with the same number and kind of chromosomes as the parent cell.
(b) Group O is recessive (genotype OO). A parent of group A can be AO and a parent of group B can be BO. If each passes on the O allele, the child is OO, group O (chance ¼ in AO x BO, AO x AO or BO x BO).
(c) Genes carry characteristics from parents to offspring; mutations change genes and produce new variations; useful variations help some individuals survive and reproduce (natural selection); these genes become more common over generations, so the population changes (evolves).
Show the genotypes and the gametes in (b).
Section B
(a)(i) What is competition? (ii) List two types of competition. (iii) List four factors that organisms compete for in a habitat. (iv) Explain briefly the relationship between competition and succession.
(b)(i) What is structural adaptation? (ii) State four types of structural adaptations in animals.
(c) List four features of variation in humans that are used in crime detection.
(d) Complete the table below by listing three types of adaptive colouration in animals and give one example each of animals that show the colourations.
Table columns: Three types of adaptive colouration in animals | One example of animal that shows the type of colouration
(e) Give three examples of plants found in a tropical Rainforest.
(a)(i) Competition is the struggle between organisms living together for resources that are in short supply.
(ii) Intraspecific (between members of the same species) and interspecific (between different species).
(iii) Any four: food/nutrients; water; light; space/territory; mates; oxygen.
(iv) During succession new species arrive and compete with those already present; better competitors replace the earlier species, and this repeated replacement continues until a stable climax community forms.
(b)(i) Structural adaptation is the possession of body structures that help an organism survive and reproduce in its habitat.
(ii) Any four: colouration (camouflage/warning); body shape, e.g. streamlined body of fish; protective coverings such as shells, spines, scales; claws and beaks; mouthparts; webbed feet; fins/gills.
(c) Any four: fingerprints; blood groups; DNA profile; facial features/shape of face; height; hair colour/texture; skin colour; handwriting/voice.
(d) Any three: camouflage (cryptic) - chameleon/grasshopper/stick insect; warning colouration - monarch butterfly/wasp/poison-arrow frog; mimicry - harmless fly resembling a wasp, viceroy butterfly; countershading - fish (dark back, light belly); disruptive colouration - zebra.
(e) Any three: mahogany; iroko; obeche; oil palm; rubber tree; ferns; climbers (lianas); epiphytes such as orchids.
In (d) give the type of colouration with an animal that clearly shows it.