48 questions. Try each one, then open the answer to check yourself and read the explanation.
The habitat of the cysticercus of Taenia solium is
Answer: B (muscles of pig)
Taenia solium is the pork tapeworm; its larval stage (cysticercus) forms cysts in the muscles of pigs, and people are infected by eating undercooked pork.
The organism that has a hydrostatic skeleton is
Answer: D (earthworm.)
The earthworm's body is supported by fluid under pressure in its coelom, which is a hydrostatic skeleton.
The possession of scales, laying of eggs with shells and bony structure of the head are characteristics shared by
Answer: A (birds and reptiles)
Reptiles and birds both lay shelled eggs, have bony skulls and have scales (birds on their legs).
The group of Arthropods that has no antennae is the
Answer: C (Arachnida)
Arachnids such as spiders and scorpions have no antennae; the other groups all have them.
The structure that is most commonly identified in all living cells under the light microscope is the
Answer: C (nucleus)
The nucleus is large and easily stained, so it is the organelle most readily seen with a light microscope.
Which of the following is an organ?
Answer: B (Liver)
An organ is made of several tissues working together; the liver is an organ, while the others are cells or tissues.
Use the diagram to answer questions 7 and 8. The structure labelled II is used for
Answer: B (feeling)
II is the antenna of the housefly, which is a sense organ for touch (feeling) and smell.
Use the diagram to answer questions 7 and 8. The structure labelled III represents the
Answer: C (proboscis)
The housefly feeds with a long proboscis ending in a spongy pad (labellum), shown as III.
The division of a body into two equal halves along a longitudinal plane is called
Answer: A (bilateral symmetry)
In bilateral symmetry only one lengthwise cut divides the body into two mirror-image halves.
In which of the following organisms does each cell combine the functions of nutrition, reproduction and growth?
Answer: D (Spirogyra.)
Spirogyra is a simple filament in which every cell photosynthesises, grows and can divide or conjugate on its own.
The key event in the transition of the amphibians from water to land is the
Answer: A (replacement of the gills with lungs)
To live on land an animal must breathe air, so replacing gills with lungs was the key change.
In plant cells, the chloroplasts are located
Answer: D (within the cytoplasm.)
Chloroplasts are organelles suspended in the cytoplasm, usually in the thin layer around the vacuole.
In woody stems, gaseous exchange takes place through the
Answer: C (lenticels)
Lenticels are loose pores in the bark of woody stems that allow air in and out.
Substances manufactured by the leaves are transported to other parts of the plant through the
Answer: C (sieve tubes)
Food made in the leaves is translocated through the sieve tubes of the phloem.
After a meal of yam has been digested, the highest concentration of glucose is to be found in the
Answer: C (hepatic portal vein)
Glucose absorbed in the small intestine goes straight to the liver in the hepatic portal vein, so it is richest there.
The dark reaction of photosynthesis involves
Answer: C (use of carbon (IV) oxide to produce glucose using ATP.)
In the dark (light-independent) stage, carbon (IV) oxide is fixed and turned into glucose using the ATP and hydrogen made in the light stage.
Mammals acclimatize to reduced oxygen content at high altitudes by
Answer: C (the stimulation of marrow to produce more erythrocytes)
With less oxygen in the air, bone marrow produces more red blood cells so the blood can still carry enough oxygen.
The modes of nutrition in Nitrobacter, Ascaris and Homo sapiens respectively are
Answer: B (chemosynthetic, parasitic and holozoic)
Nitrobacter gets energy by oxidising nitrites (chemosynthesis), Ascaris lives in the gut of its host (parasitic) and humans ingest solid food (holozoic).
The richest sources of vitamin A are
Answer: B (palm oil and carrots)
Red palm oil and carrots are rich in carotene, which the body turns into vitamin A.
The force that holds water together in the form of a stream within the xylem tube is the
Answer: A (cohesion of water molecules to one another by hydrogen bonds)
Water molecules stick to each other by hydrogen bonds (cohesion), so the column in the xylem does not break as it is pulled up.
Yellowing of leaves is a symptom associated with deficiency of
Answer: D (magnesium, nitrogen and iron.)
Magnesium and nitrogen are part of chlorophyll and iron is needed to make it, so lack of any of them causes yellow leaves (chlorosis).
The lymphatic system of mammals rejoins the blood circulatory system at the
Answer: B (subclavian vein)
Lymph collects in the thoracic duct and right lymphatic duct, which drain into the subclavian veins.
In dissection, the rib cage of a mammal has to be opened in order to expose the
Answer: C (heart)
The heart and lungs lie inside the rib cage, so it must be cut open to see them.
Fertilization in humans usually takes place in the
Answer: D (upper part of the oviduct.)
Sperm meet the egg in the upper third of the oviduct (Fallopian tube), close to the ovary.
Insects visit flowers in order to
Answer: A (feed on the nectar)
Insects come for food (nectar and pollen); pollination happens by accident as they move between flowers.
In epigeal germination, the cotyledons are
Answer: A (carried above the ground by the elongating hypocotyl)
In epigeal germination (e.g. bean) the hypocotyl grows fast and pushes the cotyledons above the soil.
Bacteria multiply rapidly by means of
Answer: C (binary fission)
A bacterium grows and then splits into two identical cells, which is binary fission.
The correct sequence for the perception of smell in mammals is
Answer: D (dissolved chemicals → sensory cells → olfactory nerve → brain.)
Chemicals dissolve in the nasal mucus, stimulate sensory cells, and impulses travel along the olfactory nerve to the brain.
Use the diagram to answer questions 29 and 30. The part labelled III is for
Answer: B (insulation)
III is the layer of fat under the skin, which insulates the body against heat loss.
Use the diagram to answer questions 29 and 30. The structure labelled II is known as
Answer: A (sweat gland)
II points to the coiled tube deep in the dermis, which is the sweat gland.
In mammals, the organ which performs digestive and endocrine functions is the
Answer: B (pancreas)
The pancreas makes digestive enzymes and also releases the hormones insulin and glucagon into the blood.
The chitin in the exoskeleton of many arthropods is strengthened by
Answer: D (proteins.)
In insects the chitin is hardened by tanned proteins (sclerotin); crustaceans also add calcium salts.
Use the diagram to answer questions 33 and 34. The structure labelled II articulates with III to form a
Answer: B (hinge joint)
II and III meet at the elbow, which bends in one plane only, so it is a hinge joint.
Use the diagram to answer questions 33 and 34. Which of the bones is the radius?
Answer: D (IV)
The radius is one of the two forearm bones between the elbow and the wrist, labelled IV.
The construction of dams may lead to an increase in the prevalence of
Answer: D (malaria, bilharziasis and onchocerciasis.)
Dams create still and fast-flowing water where mosquitoes, snails and blackflies breed, spreading malaria, bilharzia and river blindness.
Floating microscopic heterotrophs are mostly grouped as
Answer: B (zooplankton)
Zooplankton are tiny drifting animals that feed on other organisms; phytoplankton make their own food.
Vaccination is carried out in order to
Answer: D (stimulate the production of antibodies)
A vaccine contains weakened or dead germs that make the body produce antibodies, giving immunity.
A soil consisting of alumina and iron (II) oxide is known as
Answer: C (laterite)
Laterite forms in hot, wet regions where leaching leaves mainly iron and aluminium oxides.
The sign + is used to indicate an association where an organism gains, while 0 is used where an organism is unaffected. An association indicated as + 0 is known as
Answer: B (commensalism)
In commensalism one partner benefits (+) and the other is neither helped nor harmed (0).
Which of the following characterizes the white mangrove?
Answer: C (Breathing roots)
The white mangrove grows in waterlogged mud and sends up breathing roots (pneumatophores) to get air.
If the offspring of a cross between a brown mouse (bb) and a black mouse (BB) are allowed to interbreed, how many different genotypes would result?
Answer: B (3)
The first cross gives all Bb. Crossing Bb × Bb gives BB, Bb and bb, which is 3 genotypes.
The biological factor that is unique to each individual is the
Answer: A (DNA)
Except for identical twins, every person's DNA sequence is different, which is why DNA fingerprinting works.
From an evolutionary standpoint, the older a fossil-bearing rock is, the more likely it is to contain
Answer: B (invertebrates as opposed to vertebrates)
Simpler organisms appeared first, so older rocks contain invertebrates and newer rocks contain vertebrates.
The very bright colours in some types of mushroom
Answer: A (are a warning that they may be poisonous)
Bright colours often warn animals that the mushroom is poisonous (warning colouration).
The least adaptive feature for arboreal life is the
Answer: D (shading of coat colour.)
Limbs, claws and a long tail all help an animal climb and balance in trees; coat shading does not help tree life.
Which of the following is one of Lamarck's theories?
Answer: D (New species originate through the inheritance of acquired traits.)
Lamarck proposed that traits acquired during life are passed on to offspring; the others are Darwin's ideas.
The loud cry made by a brooding hen when a predator is around is meant to
Answer: D (warn its chicks and other chickens of impending danger.)
It is an alarm call that warns the chicks and other birds to hide.
The most important environmental factor which epiphytes in the rain forest compete for is
Answer: C (light)
The rain forest floor is shaded, so epiphytes perch on tall trees to reach sunlight for photosynthesis.