IGCSE Biology Practice Test 9 – 60 Questions with Answers (Cambridge 0610)
Use this test to practise applying your knowledge, not just recalling facts, and read every option before you choose.
Characteristics and classification of living organisms
Q1. Which group of animals has a moist skin, lays eggs in water, and lives on land as an adult?
- (A) Reptiles with scaly skin
- (B) Fish
- (C) Amphibians
- (D) Birds
Show Answer
Answer: C – Amphibians such as frogs have a moist skin for gas exchange and a water-dependent larval stage.
Q2. Which feature distinguishes a mammal from a bird?
- (A) Mammals have hair and produce milk
- (B) Mammals lay hard-shelled eggs like birds do
- (C) Mammals have feathers
- (D) Mammals have a beak
Show Answer
Answer: A – Mammals are defined by hair and mammary glands, while birds have feathers and lay eggs.
Q3. Which organism is a prokaryote?
- (A) Chlorella
- (B) Yeast
- (C) Amoeba
- (D) Bacterium
Show Answer
Answer: D – Bacteria have no true nucleus, unlike eukaryotic protoctists, fungi, plants and animals.
Organisation of the organism
Q4. Which tissue in a plant root is specialised for absorption?
- (A) Xylem
- (B) Root hair tissue
- (C) Phloem
- (D) Leaf mesophyll tissue in leaves
Show Answer
Answer: B – Epidermal cells with root hairs increase surface area for absorbing water and ions.
Q5. Which organ in the human body filters blood and forms urine?
- (A) Liver
- (B) Spleen
- (C) Bladder
- (D) Kidney
Show Answer
Answer: D – Each kidney contains thousands of tubules that filter blood and produce urine.
Q6. Which example shows a system working with another system?
- (A) A single muscle cell contracting repeatedly on its own
- (B) A chloroplast absorbing light
- (C) The heart pumping blood to muscles during exercise
- (D) A root hair absorbing water
Show Answer
Answer: C – The circulatory system supplies the muscular system with oxygen and glucose during exercise.
Movement into and out of cells
Q7. Which particles move by diffusion?
- (A) Particles moving from high to low concentration
- (B) Particles moving only with energy input from respiration
- (C) Water molecules only
- (D) Large proteins through cell walls
Show Answer
Answer: A – Diffusion is the net movement of particles down a concentration gradient.
Q8. What happens to a plant cell placed in a concentrated salt solution?
- (A) Water enters by osmosis and the cell becomes turgid but does not burst
- (B) Water leaves by osmosis and the cell becomes plasmolysed
- (C) Salts enter by diffusion through the membrane into the cell
- (D) The membrane dissolves
Show Answer
Answer: B – Water leaves the cell by osmosis, so the cytoplasm shrinks and pulls away from the cell wall.
Q9. Which particles can pass through a partially permeable membrane most easily?
- (A) Large protein molecules, which are too big to fit through the tiny pores
- (B) Starch grains
- (C) Small molecules such as water
- (D) Whole cells
Show Answer
Answer: C – Small molecules pass through the pores of a partially permeable membrane, while larger ones are blocked.
Biological molecules
Q10. Which food sample would give a positive emulsion test?
- (A) Pure glucose solution in water
- (B) Starch suspension
- (C) Egg white solution
- (D) Cooking oil mixed with water
Show Answer
Answer: D – Oil forms a milky emulsion when shaken with ethanol and water in the emulsion test.
Q11. Which carbohydrate is used to build plant cell walls?
- (A) Cellulose
- (B) Glucose
- (C) Glycogen stored in animals
- (D) Maltose
Show Answer
Answer: A – Cellulose fibres give plant cell walls their strength and structure.
Enzymes
Q12. Which factor does NOT affect the rate of an enzyme-controlled reaction?
- (A) Temperature
- (B) The colour of the container
- (C) pH
- (D) Substrate concentration in the mixture
Show Answer
Answer: B – Temperature, pH, enzyme and substrate concentration affect rate, but container colour does not.
Q13. An enzyme is placed in strong acid and then returned to its optimum pH, but it no longer works. Why?
- (A) It was used up during the reaction and could not be recovered
- (B) It dissolved completely
- (C) It changed into substrate
- (D) It was denatured and its active site shape was lost
Show Answer
Answer: D – Extreme pH denatures enzymes, and the change in shape is usually permanent.
Plant nutrition
Q14. Which gas is taken in by leaves during photosynthesis?
- (A) Carbon dioxide
- (B) Oxygen
- (C) Nitrogen from the air
- (D) Hydrogen
Show Answer
Answer: A – Leaves absorb carbon dioxide through stomata for photosynthesis.
Q15. Which pigment absorbs light energy for photosynthesis?
- (A) Melanin
- (B) Haemoglobin
- (C) Chlorophyll
- (D) Carotene only in roots
Show Answer
Answer: C – Chlorophyll in chloroplasts absorbs mainly red and blue light for photosynthesis.
Human nutrition
Q16. Which mineral is needed to make haemoglobin?
- (A) Calcium
- (B) Iron
- (C) Iodine
- (D) Potassium
Show Answer
Answer: B – Iron is a central part of haemoglobin, and deficiency causes anaemia.
Q17. Where does most chemical digestion of fats take place?
- (A) Small intestine
- (B) Mouth
- (C) Stomach with acid conditions
- (D) Colon
Show Answer
Answer: A – Bile emulsifies fats and lipase from the pancreas digests them in the small intestine.
Q18. Which condition is caused by a lack of calcium or vitamin D?
- (A) Anaemia
- (B) Rickets
- (C) Scurvy
- (D) Kwashiorkor
Show Answer
Answer: B – Rickets causes soft, weak bones in children due to poor calcium uptake.
Transport in plants
Q19. Which structure in a leaf controls water loss?
- (A) Xylem vessel
- (B) Palisade cell in the leaf
- (C) Midrib
- (D) Stoma with guard cells
Show Answer
Answer: D – Guard cells open and close the stoma, controlling gas exchange and water loss.
Q20. From which part of a plant are sugars transported in phloem?
- (A) Roots only
- (B) Flowers only during flowering
- (C) Leaves as sources
- (D) Seeds only
Show Answer
Answer: C – Photosynthesising leaves are the main sources of sucrose for translocation.
Q21. Which statement about transpiration is correct?
- (A) It is the movement of sugars in phloem to sinks
- (B) It is the uptake of water by roots
- (C) It is the loss of water vapour from leaves
- (D) It is the opening of flowers
Show Answer
Answer: C – Transpiration is evaporation of water from leaf surfaces, mainly through stomata.
Transport in animals
Q22. Which component of blood transports dissolved food, hormones and urea?
- (A) Red blood cells
- (B) Platelets
- (C) White blood cells
- (D) Plasma
Show Answer
Answer: D – Plasma is the liquid part of blood that carries solutes around the body.
Q23. What happens to heart rate during vigorous exercise?
- (A) It increases to supply muscles faster
- (B) It decreases to save energy during exercise
- (C) It stays the same
- (D) It stops between beats
Show Answer
Answer: A – Faster heart rate delivers more oxygen and glucose and removes carbon dioxide faster.
Q24. Which vessel carries deoxygenated blood from the body back to the heart?
- (A) Aorta
- (B) Vena cava
- (C) Pulmonary vein
- (D) Coronary artery
Show Answer
Answer: B – The vena cava returns low-oxygen blood to the right atrium.
Diseases and immunity
Q25. Which statement about vaccination is correct?
- (A) It triggers active immunity and memory cell formation
- (B) It gives antibodies that last for life without memory cells
- (C) It kills all pathogens in the body at once
- (D) It works only against bacteria
Show Answer
Answer: A – A vaccine exposes the immune system to a harmless antigen, producing memory cells.
Q26. Which defence traps pathogens in the airways?
- (A) Stomach acid
- (B) Blood clotting at a wound site
- (C) Mucus and cilia
- (D) Skin oils
Show Answer
Answer: C – Mucus traps particles and cilia sweep them away from the lungs.
Q27. Which pathogen is treated with antibiotics?
- (A) HIV virus
- (B) Bacteria causing a throat infection
- (C) Malaria protoctist only with antimalarials
- (D) Fungal spores only
Show Answer
Answer: B – Antibiotics target bacteria, so they are effective against bacterial infections.
Gas exchange in humans
Q28. Which muscle is the main muscle of breathing?
- (A) Biceps
- (B) Intercostal muscle only
- (C) Abdominal muscle only
- (D) Diaphragm
Show Answer
Answer: D – The diaphragm contracts and flattens to draw air into the lungs.
Q29. Why is the air in the alveoli kept moist?
- (A) To prevent gas exchange
- (B) To dissolve oxygen for diffusion into the blood capillaries
- (C) To keep gases dissolved so they can diffuse across cells
- (D) To cool the blood
Show Answer
Answer: C – Gases must dissolve in the moist lining before they can diffuse across the alveolar wall.
Q30. Which change in the chest causes inhalation?
- (A) Volume falls and pressure rises above air pressure
- (B) Ribs move down and in
- (C) Diaphragm relaxes and domes up
- (D) Volume rises and pressure falls below air pressure
Show Answer
Answer: D – Increased volume lowers pressure, so air flows into the lungs.
Respiration
Q31. Which statement describes the energy released in respiration?
- (A) It is used for life processes such as growth and movement
- (B) It is stored as light in cells
- (C) It is lost as starch
- (D) It is only used by muscles
Show Answer
Answer: A – Energy from respiration powers active transport, synthesis, movement and keeping warm.
Q32. Which product of anaerobic respiration in muscle causes cramp and fatigue?
- (A) Ethanol
- (B) Lactic acid
- (C) Carbon dioxide
- (D) Water
Show Answer
Answer: B – Lactic acid builds up when muscles respire without enough oxygen.
Q33. Which gas is absorbed by a respiring organism and used to release energy?
- (A) Carbon dioxide
- (B) Nitrogen
- (C) Hydrogen
- (D) Oxygen
Show Answer
Answer: D – Oxygen is the final acceptor in aerobic respiration, allowing full breakdown of glucose.
Excretion in humans
Q34. Which substance is filtered out of blood but then fully reabsorbed in a healthy kidney?
- (A) Glucose
- (B) Urea
- (C) Water
- (D) Salt
Show Answer
Answer: A – Glucose is filtered at the glomerulus and reabsorbed in the first part of the tubule.
Q35. Which hormone increases water reabsorption in the kidney?
- (A) Insulin
- (B) Adrenaline
- (C) Antidiuretic hormone
- (D) Auxin
Show Answer
Answer: C – Antidiuretic hormone makes collecting ducts more permeable to water.
Q36. Which organ excretes carbon dioxide?
- (A) Kidney, which filters urea and excess salts from the blood to form urine
- (B) Lungs
- (C) Skin
- (D) Liver
Show Answer
Answer: B – Carbon dioxide diffuses from the blood into the alveoli and leaves the body in exhaled air.
Coordination and response
Q37. Which part of the nervous system coordinates a reflex action in the spinal cord?
- (A) Brain only
- (B) Receptor only
- (C) Effector only
- (D) Relay neurone in the spinal cord
Show Answer
Answer: D – Relay neurones in the central nervous system connect sensory and motor neurones in a reflex.
Q38. Which response is an example of phototropism?
- (A) Roots growing downwards
- (B) A shoot bending towards light
- (C) A leaf closing at night
- (D) A flower opening in spring
Show Answer
Answer: B – Phototropism is growth in response to light direction.
Q39. Which eye structure focuses light onto the retina?
- (A) Pupil
- (B) Sclera
- (C) Lens
- (D) Blind spot
Show Answer
Answer: C – The lens refracts light and, with the cornea, focuses an image on the retina.
Drugs
Q40. Which effect does tar in tobacco smoke have on the lungs?
- (A) It coats airways and damages cilia
- (B) It increases oxygen uptake
- (C) It strengthens alveoli
- (D) It prevents infection
Show Answer
Answer: A – Tar deposits in airways, paralyses cilia and increases risk of bronchitis and cancer.
Q41. Which statement about antibiotics and resistance is correct?
- (A) Antibiotics should be stopped as soon as symptoms improve
- (B) Completing a course reduces the chance of resistant bacteria surviving
- (C) Antibiotics work better in larger random doses
- (D) Resistance only affects viruses
Show Answer
Answer: B – Finishing the course kills more bacteria, leaving fewer resistant survivors.
Q42. Which drug is classified as a depressant?
- (A) Alcohol
- (B) Caffeine
- (C) Nicotine
- (D) Cocaine
Show Answer
Answer: A – Alcohol slows nervous activity, while caffeine, nicotine and cocaine are stimulants.
Reproduction
Q43. After fertilisation in a flowering plant, what does the ovary develop into?
- (A) Seed
- (B) Pollen grain
- (C) Stigma
- (D) Fruit
Show Answer
Answer: D – After fertilisation, the ovary wall develops into the fruit, which encloses the seeds.
Q44. Which plant structure develops into a fruit after fertilisation?
- (A) Stigma
- (B) Anther
- (C) Ovary wall
- (D) Petal
Show Answer
Answer: C – After fertilisation the ovary develops into a fruit containing seeds.
Q45. Which advantage does asexual reproduction give a plant in a stable environment?
- (A) More genetic variation
- (B) Rapid production of many identical offspring
- (C) Better dispersal by seeds
- (D) Resistance to new diseases
Show Answer
Answer: B – Asexual reproduction is fast and preserves successful traits, but gives no variation.
Inheritance
Q46. Which pair of alleles would show a recessive phenotype?
- (A) AA
- (B) Aa
- (C) AB
- (D) aa
Show Answer
Answer: D – A recessive trait appears only when both alleles are recessive.
Q47. What is the chance that a baby will be a boy, based on sex chromosomes?
- (A) 1 in 2
- (B) 1 in 4
- (C) 3 in 4
- (D) 1 in 1
Show Answer
Answer: A – A sperm carries X or Y with equal chance, while eggs always carry X.
Q48. Which molecule carries instructions for making proteins?
- (A) Lipid
- (B) Starch
- (C) DNA
- (D) Glycogen
Show Answer
Answer: C – The base sequence in DNA codes for the amino acid sequence of proteins.
Variation and selection
Q49. Which example is mainly environmental variation?
- (A) Blood group
- (B) Scarring from an injury
- (C) Eye colour
- (D) Natural hair colour
Show Answer
Answer: B – A scar is acquired during life and is not passed to offspring.
Q50. Which statement best explains why a species may become extinct?
- (A) All individuals reproduce equally
- (B) The environment stays unchanged
- (C) New food sources appear
- (D) The environment changes faster than the species can adapt
Show Answer
Answer: D – If variation cannot keep up with change, the species may die out.
Q51. In selective breeding for milk yield, which cows are chosen as parents?
- (A) Those giving the most milk
- (B) Those giving the least milk
- (C) Those chosen at random
- (D) Those that are youngest only
Show Answer
Answer: A – Breeders select the highest-yielding animals to pass on favourable alleles.
Organisms and their environment
Q52. In a food chain, what is a herbivore?
- (A) An organism that makes its own food
- (B) An organism that breaks down dead material
- (C) An animal that feeds on plants
- (D) An animal that eats other animals
Show Answer
Answer: C – A herbivore is a consumer that feeds on producers, such as a rabbit eating grass.
Q53. Which process in the nitrogen cycle is carried out by denitrifying bacteria?
- (A) Converting nitrates back to nitrogen gas
- (B) Converting ammonium to nitrites
- (C) Converting nitrites to nitrates
- (D) Converting nitrogen gas to nitrates
Show Answer
Answer: A – Denitrifying bacteria in waterlogged soil return nitrogen gas to the atmosphere.
Q54. Which statement about energy flow in a food chain is correct?
- (A) Energy is recycled like nutrients
- (B) Energy increases at each trophic level
- (C) All energy eaten becomes new biomass
- (D) Energy is lost at each transfer and is not recycled
Show Answer
Answer: D – Energy flows one way and is lost as heat, so food chains are usually short.
Human influences on ecosystems
Q55. Which human activity can cause acid rain?
- (A) Planting large areas of trees that absorb carbon dioxide from the atmosphere
- (B) Burning fossil fuels that release sulfur dioxide
- (C) Using drip irrigation
- (D) Crop rotation
Show Answer
Answer: B – Sulfur dioxide from burning coal and oil dissolves in rainwater to form acid rain, which damages trees and lakes.
Q56. Which gas, released from fertilisers and animal waste, contributes to global warming?
- (A) Oxygen
- (B) Argon
- (C) Methane
- (D) Nitrogen
Show Answer
Answer: C – Methane from livestock and rice fields is a potent greenhouse gas.
Q57. Which action best reduces the demand for land cleared for farming?
- (A) Increasing crop yields on existing farmland
- (B) Clearing more forest each year
- (C) Growing crops with lower yields
- (D) Abandoning irrigation
Show Answer
Answer: A – Higher yields from existing land reduce pressure to clear new habitat.
Biotechnology and genetic modification
Q58. Which biotechnology process makes yoghurt?
- (A) Photosynthesis by algae
- (B) Fermentation by bacteria
- (C) Genetic modification of cows
- (D) Digestion by enzymes in the gut
Show Answer
Answer: B – Lactobacillus bacteria ferment lactose in milk to lactic acid, thickening it into yoghurt.
Q59. Which step comes first in producing human insulin by genetic engineering?
- (A) Bacteria divide many times
- (B) Insulin is purified from bacteria
- (C) The insulin gene is copied
- (D) The human insulin gene is cut out using a restriction enzyme
Show Answer
Answer: D – The gene is first isolated with a restriction enzyme before insertion into a plasmid.
Q60. Which is a possible benefit of genetically modified golden rice?
- (A) It grows without water
- (B) It needs no sunlight
- (C) It provides vitamin A precursor to prevent deficiency
- (D) It cures all eye diseases
Show Answer
Answer: C – Golden rice produces beta-carotene, which the body converts to vitamin A.
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