61 questions. Try each one, then open the answer to check yourself and read the explanation.
Which of the following organisms does not exist as a single cell?
Answer: C (Volvox)
Volvox is a colony of many cells living together in a hollow ball; the others are single-celled.
Which of the following features of Paramecium is not an advancement over Amoeba? The possession of
Answer: D (nucleus)
Amoeba also has a nucleus, so having one is no advance; the fixed shape, cilia and oral groove are features Amoeba lacks.
Which of the following diseases results from the deficiency of insulin?
Answer: D (Diabetes)
Without enough insulin the body cannot control blood sugar, so the sugar level stays high: diabetes mellitus.
Root hairs absorb water from the soil by
Answer: B (osmosis)
The cell sap of root hairs is more concentrated than soil water, so water enters through the membrane by osmosis.
One of the similarities between algae and mosses is their possession of
Answer: A (chlorophyll)
Both algae and mosses are green and make their own food with chlorophyll; algae have no stems, leaves or roots.
The vessel that carries blood from the heart to the lungs is called an artery because it
Answer: C (carries blood away from the heart)
Any vessel carrying blood away from the heart is an artery, even the pulmonary artery, which carries deoxygenated blood.
During anaerobic respiration in skeletal muscles, pyruvic acid is
Answer: A (reduced to lactic acid)
Without enough oxygen, muscle cells add hydrogen to pyruvic acid (a reduction), turning it into lactic acid.
Use the information on the stages involved in conjugation to answer this question.
I. Transfer of one cell content into the adjacent cell II. Formation of a conjugation tube III. Secretion of thick wall to form a zygospore IV. Formation of a protuberance V. Germination of a filament
Which of the following organisms exhibits the stages listed above during conjugation?
Answer: C (Spirogyra)
Spirogyra filaments lying side by side join by conjugation tubes, and the contents of one cell pass into the other to form a zygospore.
Use the information on the stages involved in conjugation to answer this question.
I. Transfer of one cell content into the adjacent cell II. Formation of a conjugation tube III. Secretion of thick wall to form a zygospore IV. Formation of a protuberance V. Germination of a filament
Which of the following arrangements is the correct sequence of the process?
Answer: B (IV, II, I, III and V)
Bumps grow out first (IV), join into a tube (II), the contents pass across (I), the zygote forms a thick-walled zygospore (III) and later germinates into a new filament (V).
The teeth used for tearing and cutting are
Answer: D (canine and incissors)
Canines are pointed for tearing and incisors are chisel-shaped for cutting; premolars and molars grind.
Turgor pressure occurs in a cell when the
Answer: A (volume of its cell sap increases)
When a plant cell takes in water its sap swells and pushes the cytoplasm against the cell wall; this push is turgor pressure.
Which of the following bones is illustrated in the diagram?
Answer: D (Scapula)
The flat, triangular blade with a socket at its lower end is the shoulder blade, the scapula.
The part labelled I in the diagram is for the attachment of
Answer: C (shoulder muscles)
The broad flat blade and spine of the scapula give a large surface for the attachment of shoulder muscles.
Which of the following bones forms a joint at the point labelled II in the diagram?
Answer: A (Humerus)
II is the glenoid cavity, the socket into which the head of the humerus fits to form the shoulder (ball and socket) joint.
Terrestrial plants exchange gases through the following except
Answer: A (chloroplast)
Gases enter and leave a plant through stomata, lenticels and the surface of root cells; the chloroplast is an organelle inside cells, not an opening.
Which of the following is not a function of the liver in mammals?
Answer: D (Filtation of urea from the blood)
Urea is made in the liver but filtered out of the blood by the kidneys.
Iodine is needed by a patient suffering from a malfunctioning of the
Answer: B (thyroid gland)
The thyroid gland uses iodine to make thyroxine; lack of iodine causes goitre.
The medulla oblongata controls all the following except
Answer: D (balance and posture)
Balance and posture are controlled by the cerebellum; the medulla controls automatic actions like heartbeat and breathing.
Which of the following statements about short sight is not correct?
Answer: A (The eyeball is too short)
In short sight the eyeball is too long, not too short, so images form in front of the retina.
Hypermetropia is corrected by the use of
Answer: B (convex lenses)
In long sight (hypermetropia) images form behind the retina; a converging (convex) lens brings them forward onto it.
The structure labelled I is the
Answer: A (oviduct)
I marks the coiled tube leading from the ovary towards the uterus, the oviduct (Fallopian tube).
In which of the labelled structures does implantation take place?
Answer: C (IV)
The embryo implants in the thick wall of the uterus, labelled IV.
Which of the following indicates the direction of the movement of a sperm introduced into the female reproductive system?
Answer: B (VI → V → IV → I)
Sperm are placed in the vagina (VI) and swim through the cervix (V) and uterus (IV) into the oviduct (I).
Which of the labelled parts is responsible for the release of ripe ovum?
Answer: B (III)
III marks the ovary, which releases the ripe ovum at ovulation.
During the germination of seeds water is taken in by the process of
Answer: C (imbibition)
Dry seeds soak up water into their cell walls and food stores by imbibition, which makes them swell.
Which of the following is not a characteristics feature of a wind dispersed fruit?
Answer: D (Buoyancy)
Buoyancy (ability to float) suits fruits dispersed by water, such as coconut; wind-dispersed fruits are light with wings or hairs.
During photosynthesis, light energy is always absorbed by the
Answer: C (chlorophyll)
Chlorophyll is the green pigment that traps light energy for photosynthesis.
Use the information below on factors required during photosynthesis to answer this question.
I. CO2 II. Chlorophyll III. Water IV. ATP V. NADPH2
The factors required for the dark phase of photosynthesis are
Answer: D (IV and V only)
The dark stage uses ATP and NADPH2 from the light stage (with CO2) to make sugar; water is used only in the light stage.
In water culture experiments, the culture solutions are protected from sunlight in order to
Answer: B (prevent algae from growing in the solution)
Algae would grow in a lit solution and use up its minerals, spoiling the experiment, so the jars are kept dark.
The importance of a balanced diet is to
Answer: D (provide good health for an individual)
A balanced diet supplies all food classes in the right amounts, keeping a person healthy.
The dentition of a herbivore is distinct from that of other animals due to the presence of
Answer: A (diastema)
Herbivores such as sheep have a gap (diastema) between the front teeth and the cheek teeth, where the tongue moves the grass.
Which of the following statements is true?
Answer: C (Pepsin acts on proteins to give peptide)
Pepsin in the stomach breaks proteins into peptides; ptyalin acts on starch and lactase on lactose.
Which of the following organisms can be found in fresh water habitat?
Answer: D (Spirogyra and pond skater)
Spirogyra and the pond skater live in ponds and streams; Sargassum, dogfish and red mangrove are marine or brackish.
Which of the following is not a biotic factor?
Answer: D (Pressure)
Pressure is a physical (abiotic) factor; parasites, predators and grazers are living things.
Desert plants are usually called
Answer: C (xerophytes)
Xerophytes are plants adapted to very dry places such as deserts.
The secchi disc is used to measure
Answer: C (turbidity of water)
The depth at which the black-and-white Secchi disc disappears shows how cloudy (turbid) the water is.
Soil factors in an ecosystem are referred to as
Answer: D (edaphic)
Edaphic factors are soil factors such as texture, pH and water content.
A known weight of soil sample was oven-dried to obtain a constant weight. The loss in weight was due to loss of
Answer: B (water only)
Heating in an oven at about 100 °C drives off only the water; organic matter is removed by strong heating (burning) of the dried soil.
Carbon is added to the atmosphere by the following processes except
Answer: C (photosynthesis)
Photosynthesis takes carbon dioxide out of the air; the others release it.
Which of the following is a means of measuring primary production?
Answer: D (Harvested plants in a unit area)
Primary production is the food made by plants, measured by the mass of plant material produced in a unit area.
A situation whereby some mammals remain inactive throughout dry and hot seasons is known as
Answer: A (aestivation)
Aestivation is a resting, inactive state during hot, dry periods (hibernation is the winter version).
Which of the following factors may not affect living organisms in an aquatic habitat?
Answer: C (Humidity)
Humidity is the amount of water vapour in air, which matters on land; organisms living in water are not affected by it.
Which of the following parasites is a flatworm?
Answer: D (Schistosoma)
Schistosoma (the blood fluke) is a flatworm; Plasmodium and Trypanosoma are protozoa and Ascaris is a roundworm.
During prolonged exercises, glucose in the muscle is converted to
Answer: B (lactic acid)
When muscles run short of oxygen during long exercise, they respire anaerobically and form lactic acid.
Which of the following is an effect of carbon monoxide on man?
Answer: B (Reducing oxygen carrying capacity of blood)
Carbon monoxide binds tightly to haemoglobin, so less oxygen can be carried by the blood.
The major types of man's finger prints do not include
Answer: C (simple)
Fingerprint patterns are arches, loops, whorls and compound (composite) prints; there is no 'simple' type.
Which of the following is an example of discontinuous variation?
Answer: C (Blood groups of patients)
Blood groups fall into distinct classes (A, B, AB, O) with no in-between forms, which is discontinuous variation.
Which of the following statements is correct about variation?
Answer: D (offsprings differ from their ancestors and from each other)
Because of variation, no two offspring are exactly alike, and they differ from their parents and ancestors too.
Which of the following statements about sex determination is correct? At fertility
Answer: A (the probability of male to female offspring is 1/2)
Half the father's sperm carry X and half carry Y, so each child has an equal (1/2) chance of being male or female.
The genotypic ratio of 1 : 2 : 1 in the offspring of a hybrid cross illustrates the law of
Answer: C (segregation)
Crossing two hybrids (Tt × Tt) gives TT : Tt : tt in the ratio 1 : 2 : 1 because the two alleles separate (segregate) into different gametes.
Which of the following scientists was involved with organic evolution?
Answer: B (Larmarck)
Lamarck proposed an early theory of evolution (use and disuse, inheritance of acquired characters).
Which of the following traits may not be important in marriage counselling?
Answer: A (Sex-determination)
The sex of a child cannot cause health problems, while sickle-cell genes and the Rhesus factor can; so sex determination is not a counselling issue.
In fishes, the brooders return to their parents mouth for
Answer: D (protection)
Mouth-brooding fish such as tilapia let their young swim back into the parent's mouth when danger threatens.
According to Charles Darwin's Theory of Evolution, natural selection involves the survival of the
Answer: D (fittest)
Darwin said the individuals best suited to their surroundings survive and reproduce: survival of the fittest.
Which of the following habitats cannot be used for the study of succession?
Answer: D (Well cultivated land)
Succession needs land left to change naturally; on well cultivated land people keep removing the new plants.
(a) (i) Name four similarities found in plant and animal cells (ii) In a tabular list four different cells found in man and give a function for each of the cells.
(b) (i) Name the two types of cell divisions (ii) Give two examples each of life processes involved in each type of the cell divisions
(c) Name the two types of reproduction usually associated with organisms.
(a)(i) Any four: both have a cell membrane; cytoplasm; a nucleus; mitochondria; endoplasmic reticulum, ribosomes, Golgi bodies.
(ii) Any four cells with function: red blood cell – carries oxygen; white blood cell – fights infection; nerve cell (neurone) – carries impulses; muscle cell – contraction/movement; sperm – fertilises the ovum; ovum – female gamete; epithelial cell – covers and protects; bone cell – forms bone.
(b)(i) Mitosis and meiosis.
(ii) Mitosis: growth; repair of worn-out tissues/healing; asexual reproduction. Meiosis: formation of gametes (sperm, ova, pollen) for sexual reproduction; formation of spores; brings about variation.
(c) Sexual reproduction and asexual reproduction.
Mitosis makes body cells for growth and repair; meiosis makes gametes.
(a) (i) Define the term metamorphosis (ii) Name the two types of metamorphosis that organisms undergo and mention two organisms that undergo each type
(b) (i) State four economic importance of insects and name an example of each of the insects involved. (ii) List four peculiar features of social insects
(a)(i) Metamorphosis is the series of changes in form that an organism goes through from the egg to the adult.
(ii) Complete metamorphosis (egg → larva → pupa → adult): butterfly, housefly, mosquito, beetle, bee. Incomplete metamorphosis (egg → nymph → adult): cockroach, grasshopper, termite, locust.
(b)(i) Any four with an example: pollinate flowers – bee/butterfly; produce honey and wax – honeybee; produce silk – silkworm; used as food – termite/locust; carry diseases – mosquito (malaria), housefly (cholera/typhoid), tsetse fly (sleeping sickness); destroy crops and stored produce – locust, weevil; destroy wood and buildings – termite; help decay of dead matter – termites/beetles.
(ii) Any four: live together in large colonies; division of labour among castes; castes differ in structure (polymorphism); one or few reproductive members (queen and king/drones); build a common nest; communicate and cooperate (e.g. bee dance); care for the young together.
Complete metamorphosis has a pupa stage; incomplete does not.
(a)(i) What is Pollution? (ii) Name two pollutants each of air and water
(b) (i) State four effects of water pollution on organisms (ii) Mention four ways of preventing water pollution in an environment
(c) (i) Name three sources of noise pollution (ii) State three effects of noise pollution on man
(a)(i) Pollution is the release into the environment of harmful substances or energy (pollutants), in amounts that damage living things.
(ii) Air: carbon monoxide, sulphur dioxide, oxides of nitrogen, smoke/soot, dust. Water: sewage, crude oil, fertilisers, pesticides, industrial chemicals/heavy metals, refuse.
(b)(i) Any four: death of fish and other aquatic organisms; less dissolved oxygen (eutrophication from sewage and fertilisers); spread of water-borne diseases (cholera, typhoid); poisoning of organisms and accumulation along food chains; oil coats birds' feathers and fish gills; water becomes unfit for drinking.
(ii) Any four: treat sewage before discharge; proper disposal of refuse; treat industrial waste before release; avoid excessive use of fertilisers and pesticides; prevent oil spills and clean them up; laws and fines against polluters; public education.
(c)(i) Any three: aircraft/airports; motor vehicles and horns; factory machines and generators; loudspeakers/music; blasting, building work.
(ii) Any three: loss of hearing/deafness; headache; stress, irritability and lack of sleep; high blood pressure; poor concentration.
Name actual substances as pollutants, not just 'smoke'.
(a) (i) Define the law of independent assortment (ii) State the findings from Mendel's experiment involving white- flowered and red-flowered pea plants (iii) Illustrate these findings by means of simple diagrams
(b) Explain why blood groups A and B in man can exist both in heterozygous and homozygous conditions while blood group O can only exist in homozygous state.
(a)(i) Law of independent assortment (Mendel's second law): when two or more pairs of characters are inherited together, each pair of alleles separates into the gametes independently of the other pairs.
(ii) Crossing pure red-flowered with pure white-flowered plants gave all red-flowered plants in the F1 (red is dominant). Selfing the F1 gave red and white plants in the F2 in a ratio of 3 red : 1 white; the factors for colour separate in gamete formation.
(iii) Let R = red, r = white. Parents RR × rr; gametes R and r; F1 all Rr (red). F1 Rr × Rr; gametes R, r × R, r; F2 RR, Rr, Rr, rr = 3 red : 1 white (genotypes 1 : 2 : 1). (Diagram or Punnett square showing these.)
(b) The alleles A and B are both dominant over O (O is recessive). Group A can be AA or AO, and group B can be BB or BO, because one dominant allele is enough to show. Group O shows only when no dominant allele is present, so the person must be OO (homozygous).
Show parents, gametes, F1 and F2 clearly in the genetic diagram.
State the principles involved in the following methods of food preservation: (a) (i) Salting (ii) Refrigeration (iii) Drying (iv) Smoking (v) Chemicals
(b) State four problems that may be caused by human overpopulation
(c) Explain three ways by which the government may increase food production
(a)(i) Salting draws water out of the food and microorganisms by osmosis, so they cannot grow.
(ii) Refrigeration: low temperature slows down or stops the growth of microorganisms and enzyme action.
(iii) Drying removes water that microorganisms need to grow.
(iv) Smoking dries the food and coats it with chemicals from the smoke that kill or keep off microorganisms.
(v) Chemicals (preservatives such as sodium benzoate, vinegar, sugar) kill microorganisms or stop their growth.
(b) Any four: shortage of food/famine; overcrowding and poor housing (slums); spread of diseases; unemployment; pollution and poor sanitation; pressure on social amenities (schools, hospitals, water); crime; deforestation and loss of farmland.
(c) Any three, explained: give farmers loans/credit and subsidised fertilisers and tools; mechanise farming; provide improved seeds and livestock through research; provide irrigation; good storage, processing and roads to reduce waste; agricultural extension services to teach farmers; land reform to make land available.
For each preservation method, say how it stops microorganisms.
(a) (i) Define the term hydrosphere (ii) Give three examples of hydrosphere
(b) (i) State the two laws of thermodynamics (ii) Use the second law of thermodynamics to explain the energy flow across trophic levels
(c) (i) Name two local biotic communities in Nigeria and associate each type with a particular state in Nigeria (ii) List three factors that affect organisms in the marine habitat (iii) State three adaptive features of sea weeds.
(a)(i) The hydrosphere is the water part of the earth's surface.
(ii) Any three: oceans/seas, rivers, lakes, ponds, streams, lagoons.
(b)(i) First law: energy can neither be created nor destroyed, but can be changed from one form to another. Second law: whenever energy is changed from one form to another, some of it is lost as heat, so no transfer is 100% efficient.
(ii) At each trophic level much of the energy taken in is lost as heat in respiration (and in waste), so only a small part (about 10%) passes to the next level; energy therefore decreases up the food chain, which limits the number of trophic levels.
(c)(i) Any two with a matching state: tropical rainforest – e.g. Ondo/Cross River/Edo; mangrove swamp – e.g. Rivers/Bayelsa/Lagos; Guinea savanna – e.g. Kwara/Niger/Kaduna; Sudan savanna – e.g. Kano/Sokoto; Sahel savanna – e.g. Borno; montane forest – e.g. Plateau/Taraba.
(ii) Any three: salinity; temperature; light/turbidity; waves and tides; dissolved oxygen; pressure/depth; ocean currents.
(iii) Any three: holdfasts to anchor them to rocks; air bladders to float near the light; slimy/mucilaginous covering to resist drying at low tide; tough flexible body that resists wave action; extra pigments to absorb light under water.
Second law: energy is lost as heat at every transfer.