50 questions. Try each one, then open the answer to check yourself and read the explanation.
An example of organ level of organization is
Answer: B (kidney.)
The kidney is an organ: it is made of several tissues working together. A bird is a whole organism, a sperm is a cell and xylem is a tissue.
A structural similarity between Paramecium and Amoeba is the presence of
Answer: A (one food vacuole.)
Both organisms digest food inside food vacuoles. Only Paramecium has two contractile vacuoles, two nuclei and a gullet (oral groove).
The classes of plants the root systems in diagrams I and II below represent respectively are
Answer: A (Dicotyledoneae and Monocotyledoneae.)
Diagram I shows one main root with smaller side roots: a tap root system, found in dicots. Diagram II shows many roots of similar size from the base of the stem: a fibrous root system, found in monocots.
The diagram below is an illustration of a stage in a biological process. What stage of cell division is illustrated in the diagram?
Answer: B (Metaphase)
The chromosomes are lined up across the middle (equator) of the cell, attached to spindle fibres. This is metaphase.
The diagram below is an illustration of a stage in a biological process. The part labelled I is the
Answer: C (centriole.)
Part I is at the pole of the cell, where the spindle fibres meet. This structure is the centriole.
The rate of diffusion of molecules between two media will be higher if
Answer: C (the difference in concentration of the two media is high.)
The bigger the difference in concentration (the steeper the gradient), the faster molecules diffuse from the high to the low concentration.
Anaerobic respiration in the organism illustrated in the diagram below produces carbon dioxide and
Answer: A (ethanol.)
The diagram shows budding yeast. Without oxygen, yeast ferments glucose into ethanol (alcohol) and carbon dioxide.
Muscle fatigue in the body of an athlete is due to
Answer: C (accumulation of lactic acid.)
During hard exercise muscles run short of oxygen and respire anaerobically, producing lactic acid. Lactic acid builds up and causes fatigue and cramps.
The heart can beat continuously without being fatigued because it is composed of
Answer: C (cardiac muscles.)
Cardiac muscle, found only in the heart, contracts rhythmically all through life without getting tired.
The products of tissue respiration are
Answer: D (water, carbon dioxide and energy.)
In tissue (aerobic) respiration glucose is broken down using oxygen, giving carbon dioxide, water and energy.
The process of maintaining a steady internal environment is known as
Answer: C (homeostasis.)
Homeostasis is keeping the conditions inside the body (temperature, water, sugar) steady.
Which of the following statements is not true about hormones?
Answer: A (Their responses are voluntary)
Hormones are chemical messengers carried in the blood, and one hormone can act on several organs. Their effects happen automatically, not by choice, so they are not voluntary.
The diagram below is an illustration of a human brain. The part labelled I is the
Answer: C (cerebrum.)
Part I is the large folded upper part of the brain, divided into two halves. This is the cerebrum.
The diagram below is an illustration of a human brain. The function of the part labelled II is that it controls
Answer: D (many involuntary actions.)
Part II is the medulla oblongata at the base of the brain. It controls involuntary actions such as breathing, heartbeat and swallowing.
To focus on a distant object, the ciliary muscle of the eye
Answer: B (relaxes and the eye lens gets thinner.)
For a far object the ciliary muscles relax, the suspensory ligaments become tight and pull the lens thin, so it bends light less.
The main function of the amniotic fluid is for
Answer: B (protection of the foetus from shock.)
The amniotic fluid surrounds the foetus and acts as a cushion, protecting it from bumps and shocks.
The diagram below is an illustration of the longitudinal section of a flower. Which part of the flower is responsible for the protection of young flower buds?
Answer: B (II)
Part II is the sepal. Sepals enclose and protect the flower while it is still a bud.
The diagram below is an illustration of the longitudinal section of a flower. The essential parts of the flower are labelled
Answer: D (IV, V and VI.)
The essential parts are the reproductive ones: the stamens (male) and the carpel/pistil (female). These are labelled IV, V and VI.
Deficiency in insulin could lead to
Answer: C (diabetes.)
Without enough insulin the body cannot lower its blood sugar, so sugar builds up in the blood: diabetes mellitus.
Which of the following forms of energy is utilized during photosynthesis?
Answer: C (Solar)
Photosynthesis uses light (solar) energy from the sun and turns it into chemical energy stored in food.
Light is excluded from a water culture experiment in order to
Answer: D (prevent the growth of algae.)
If light reaches the nutrient solution, algae grow in it and use up the minerals. Covering the culture bottle keeps light out and stops algae growing.
The major mineral present in the shell of Molluscs is
Answer: D (calcium.)
Snail and other mollusc shells are made mainly of calcium carbonate.
The digestion of proteins starts in the
Answer: B (stomach.)
Saliva has no protein-digesting enzyme. Protein digestion begins in the stomach, where pepsin breaks proteins into peptides.
Tooth decay is usually caused by
Answer: C (the bacteria in the mouth that metabolize sugar to acids.)
Bacteria in plaque feed on sugar left on the teeth and produce acids. The acids dissolve the enamel and cause decay.
The conversion of ammonium salts into nitrates is called
Answer: D (nitrification.)
Nitrifying bacteria (Nitrosomonas and Nitrobacter) change ammonium compounds into nitrites and then nitrates. This is nitrification.
The salinity of a brackish habitat
Answer: D (increases during the dry season.)
In the dry season less fresh river water flows in and more water evaporates, so the water becomes saltier. Rain makes it less salty.
If 90 ants are found in a field with a total area of 100 m2, what is the population density of the ants?
Answer: B (0.90)
Population density = number ÷ area = 90 ÷ 100 = 0.90 ants per m2.
The complex relationship between the members of a community and their physical environment is known as
Answer: D (ecology.)
Ecology is the study of how living things relate to one another and to their non-living surroundings.
The specific role of a species within its environment is known as its
Answer: B (niche.)
A niche is the role or position of a species in its habitat: what it eats, what eats it and how it uses resources.
Which of the following soil fertility improvement methods will have the most negative effect on the ecosystem if not controlled?
Answer: A (Application of N-P-K fertilizer)
Too much fertilizer washes into rivers and lakes and causes eutrophication, killing fish. It can also make soil acidic and harm soil organisms.
In the pyramid of energy illustrated below, the organism with the least amount of transferred energy is
Answer: D (bird.)
Energy is lost at each step of a food chain, so the top level (the bird) receives the least energy.
Tall trees with unbranched trunks which grow above the upper storey of the forest are commonly referred to as
Answer: A (emergents.)
Emergents are the very tall trees that rise above the main forest canopy.
Maize grains are best stored against insect attacks by
Answer: A (keeping in a silo.)
A silo is a sealed, dry store that keeps out insects, rodents and moisture, so the grain stays safe longest.
Cholera is mostly spread by
Answer: C (water.)
Cholera bacteria pass out in the faeces of sick people and spread mainly through contaminated drinking water (and food).
Which of the following resources is renewable?
Answer: D (Trees)
Trees can be replanted and will grow again. Petroleum, coal and iron ore cannot be replaced once used up.
Which of the following roles is not performed by a government agency responsible for forest maintenance?
Answer: D (Regulating mining activities in the forest)
A forestry agency manages forests, timber and wildlife. Mining is controlled by the mines and minerals authorities.
Which of the following factors is not a source of variation in living organisms?
Answer: C (Mitosis)
Mitosis makes daughter cells identical to the parent cell, so it produces no variation. Meiosis, inheritance and the environment all cause differences.
The diagram below is an illustration of a process occurring in a living animal cell. The process occurs in the
Answer: A (nucleus)
The diagram shows a DNA molecule unzipping and being copied into two. DNA replication takes place in the nucleus.
The diagram below is an illustration of a process occurring in a living animal cell. The process is called
Answer: A (replication.)
One DNA double helix separates and each strand is used as a template, giving two identical DNA molecules. This is DNA replication.
Which of the following nucleotides is not found in the DNA molecule?
Answer: D (Uracil)
DNA contains adenine, thymine, guanine and cytosine. Uracil replaces thymine only in RNA.
In a complete dominance monohybrid cross between a pure breeding yellow flowered plant Y and a pure breeding white flowered plant y, the result of the first filial generation is
Answer: C (all yellow flowers.)
YY × yy gives only Yy offspring. Yellow is dominant, so every F1 plant has yellow flowers.
A man whose blood group is heterozygous B is married to a woman whose blood group is also heterozygous B. Which of the following statements is correct about the blood group of their four offspring?
Answer: A (Three of them belong to blood group B)
BO × BO gives BB, BO, BO and OO. Three of the four expected children are group B and one is group O.
The cross between RrTt and rrtt where R is a gene for red colour and T for tallness will result in
Answer: B (25 % tall with red fruits.)
RrTt makes four kinds of gametes (RT, Rt, rT, rt) and rrtt makes only rt. The offspring are RrTt, Rrtt, rrTt and rrtt in equal numbers, so 1 in 4 (25%) is red and tall.
The yellow and black stripes on the body of wasps is an example of
Answer: D (warning colouration.)
Bright yellow and black stripes warn predators that the wasp can sting, so they learn to leave it alone. This is warning colouration.
The biological importance of the dance by the worker honeybee is that it
Answer: C (signals the availability of food.)
A worker bee's dance tells other workers the direction and distance of a food source it has found.
(a)(i) Complete the table below with the respiratory surface of each of the listed organisms.
Organism | Respiratory surface
Tadpole (2 days old) |
Cockroach |
Domestic fowl |
Talinum |
Earthworm |
Amoeba |
(ii) State five characteristic features of respiratory surfaces in organisms. (b) Make a drawing, 4 cm – 6 cm long of the respiratory organ in Tilapia and label fully.
(a)(i) Tadpole (2 days old): external gills.
Cockroach: tracheoles (tracheal system).
Domestic fowl: lungs (alveoli/air capillaries).
Talinum: stomata (and lenticels) – the moist surfaces of the mesophyll cells.
Earthworm: moist skin (body surface).
Amoeba: cell membrane (body surface).
(ii) Any five: large surface area; thin (one cell thick); moist; permeable to gases; well supplied with blood capillaries (where there is a blood system); well ventilated so a concentration gradient is kept.
(b) Drawing of a single gill, 4–6 cm, with title and labels: gill arch (bar), gill rakers, gill filaments (lamellae), (afferent and efferent blood vessels).
Name the actual surface across which gases pass, not just the organism's organ.
The table below shows the percentage composition of fat and protein in six different meat types. Study it and answer questions 2(a) to 2(d).
Meat type | Fat (%) | Protein (%)
A | 07.2 | 21.3
B | 25.3 | 10.6
C | 20.0 | 22.5
D | 03.1 | 28.2
E | 12.6 | 17.3
F | 13.2 | 14.3
(a)(i) Which two of the meat types may be recommended for an obese patient? (ii) State one reason for the answer in 2(a)(i). (b)(i) Which two of the meat types would provide the most energy? (ii) State two reasons for the answer in 2(b)(i). (c)(i) Which three of the meat types could be recommended for a child suffering from kwashiorkor? (ii) State one reason for the answer in 2(c)(i). (d) Which of the meat types would most likely be suitable for: (i) an active teenager; (ii) a 70 - year old human? (e) Which other class of food provides energy? (f) State three uses of fat in the human body. (g) Describe briefly the procedure for testing for fat in a meat sample using a piece of white paper.
(a)(i) A and D.
(ii) They have the lowest fat content (and are rich in protein), so they add little extra energy to be stored as fat.
(b)(i) B and C.
(ii) They have the highest fat content; fat releases about twice as much energy per gram as carbohydrate or protein when oxidised.
(c)(i) D, C and A (the highest protein: 28.2, 22.5, 21.3%).
(ii) Kwashiorkor is caused by lack of protein, so the child needs meat rich in protein.
(d)(i) Active teenager: C (high in both fat for energy and protein for growth); B or E also accepted.
(ii) 70-year-old: D (high protein for repair, very low fat).
(e) Carbohydrates.
(f) Any three: source of energy; insulation (keeps body heat in); protects delicate organs; store of food; forms part of cell membranes; dissolves and carries vitamins A, D, E and K.
(g) Rub (or press) a piece of the meat on a clean white paper; leave the paper to dry (or warm it gently); hold it up to the light; a translucent (greasy) spot that does not dry away shows that fat is present.
Read the numbers from the table carefully before choosing.
(a) Classify the following biological associations under the headings in the table below: (i) Remora and shark; (ii) Lichen; (iii) Cattle and white Egret; (iv) Tapeworm in the gut of humans; (v) Flowers and Honeybees; (vi) Mistletoe and Cacao plant.
Parasitism | Mutualism | Commensalism
(b)(i) State three adaptive features of parasites. (ii) State two effects of parasites on their hosts. (c)(i) What are saprophytes? (ii) Give four examples of saprophytes.
(a) Parasitism: tapeworm in the gut of humans; mistletoe and cacao plant.
Mutualism: lichen; flowers and honeybees.
Commensalism: remora and shark; cattle and white egret.
(b)(i) Any three: hooks and suckers (or haustoria) for attachment; thick cuticle or anti-enzymes protect against digestion by the host; reduced or no digestive system, absorb digested food; produce very large numbers of eggs/spores; hermaphrodite (self-fertilising); resistant cysts or eggs; secondary hosts help spread them; reduced sense organs and locomotory organs.
(ii) Any two: deprive host of food, causing weakness and loss of weight; cause disease; damage tissues; cause anaemia (blood loss); produce toxins; may kill the host; reduce crop yield in plants.
(c)(i) Saprophytes are organisms that feed on dead and decaying organic matter, secreting enzymes onto it and absorbing the digested products.
(ii) Any four: Rhizopus (bread mould), Mucor, mushroom, yeast, Penicillium, saprophytic bacteria.
In commensalism one partner gains and the other is not affected.
Use the information below to answer questions 4(a)(i) and 4(a)(ii). HbA represents normal haemoglobin. HbS represents sickled haemoglobin. (a) A female heterozygote for sickle cell married a sickler. With the aid of a genetic diagram, determine the: (i) possible genotypes of their offspring; (ii) phenotypic ratio of the offspring. (b) Explain briefly the reason why a Rhesus negative woman married to a Rhesus positive man might lose her second pregnancy. (c) Name two examples of features in animals that support the theory of use and disuse of body parts as used by Lamarck. (d) List three structures in mammals that are vestigial.
(a) Parents: HbAHbS (carrier) × HbSHbS (sickler).
Gametes: HbA, HbS and HbS, HbS.
(i) Offspring genotypes: HbAHbS, HbAHbS, HbSHbS, HbSHbS (AS and SS).
(ii) Phenotypic ratio 1 carrier (sickle-cell trait, normal) : 1 sickler (sickle-cell anaemia).
(b) If the first baby is Rh positive, some of its blood enters the mother's blood at birth; she makes anti-Rh (anti-D) antibodies. In the second pregnancy with an Rh-positive baby these antibodies cross the placenta and destroy (agglutinate) the baby's red blood cells (haemolytic disease of the newborn), so the baby may die.
(c) Any two: long neck of the giraffe (stretching to reach leaves); webbed feet of water birds (stretching toes while swimming); long legs of wading birds; strong arm muscles of a blacksmith; loss of eyes in cave animals and of legs in snakes (disuse).
(d) Any three: appendix (vermiform appendix); coccyx (tail bones); ear muscles (pinna muscles); wisdom teeth; body hair; nictitating membrane (plica semilunaris) in humans.
In a genetic diagram always show parents, gametes, fusion and offspring.
(a) Explain briefly the importance of the following factor and organisms in the nitrogen cycle: (i) lightning; (ii) Nitrosomonas; (iii) Azotobacter. (b) Name the excretory organ in: (i) insects; (ii) earthworm. (c) Explain briefly the following diseases: (i) hepatitis; (ii) kidney stones. (d)(i) State three effects of lack of sense receptors in the skin of humans. (ii) List three layers of the epidermis in the skin of humans. (e)(i) What is metamorphosis? (ii) State the type of metamorphosis exhibited by each of the following insects listed in the table below.
Insect | Type of metamorphosis
Grasshopper |
Cockroach |
Butterfly |
Mosquito |
Housefly |
(a)(i) Lightning: its energy makes nitrogen and oxygen in the air combine into oxides of nitrogen, which dissolve in rain and reach the soil as nitrates.
(ii) Nitrosomonas: a nitrifying bacterium that changes ammonium compounds into nitrites.
(iii) Azotobacter: a free-living nitrogen-fixing bacterium in the soil that turns atmospheric nitrogen into nitrogen compounds.
(b)(i) Insects: Malpighian tubules. (ii) Earthworm: nephridia.
(c)(i) Hepatitis: inflammation of the liver, usually caused by a virus (hepatitis A, B, C), spread through contaminated food/water or blood and body fluids; signs include jaundice, fever, tiredness; can lead to liver damage.
(ii) Kidney stones: hard deposits of salts (e.g. calcium oxalate) that form in the kidney; they can block urine flow and cause severe pain and blood in urine; linked to low water intake.
(d)(i) Any three: inability to feel pain, so injuries go unnoticed; cannot feel heat, so burns may result; cannot sense touch or pressure; cannot sense cold, so body may not respond to cold; increased risk of injury and infection.
(ii) Any three: cornified layer (stratum corneum); granular layer; Malpighian (germinative) layer.
(e)(i) Metamorphosis is the series of changes in form that an insect goes through from egg to adult.
(ii) Grasshopper: incomplete. Cockroach: incomplete. Butterfly: complete. Mosquito: complete. Housefly: complete.
Section C (candidates in Nigeria only). Incomplete metamorphosis has a nymph stage; complete metamorphosis has larva and pupa.