IGCSE Biology (0970) — May–June 2025, Paper 21

40 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.

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Question 1 · 1 mark · Characteristics and classification of living organisms

Which characteristic of living things requires carbon dioxide to diffuse into a leaf? A excretion B movement C nutrition D respiration

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Question 2 · 1 mark · Characteristics and classification of living organisms

Which set of features is characteristic only of birds? A hair and wings B hard-shelled eggs and feathers C scales and soft-shelled eggs D wings and soft-shelled eggs

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Question 3 · 1 mark · Organisation of the organism

Which structures are found in both plant and animal cells? A cell walls and cell membranes B nuclei and cell walls C cytoplasm and chloroplasts D cell membranes and nuclei

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Question 4 · 1 mark · Movement into and out of cells

A student made the following statements about the movement of ions by active transport. 1 It is the net movement of particles from a low concentration to a high concentration. 2…

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Question 5 · 1 mark · Biological molecules

A DNA molecule contains pairs of bases. What is a correct combination of a pair of bases? A A and G B C and A C G and T D T and A

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Question 6 · 1 mark · Biological molecules

What is the test for protein? name of the test heat colour change --- --- --- --- A Benedict's yes blue to purple B biuret yes blue to red C biuret no blue to purple D Benedict's…

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Question 7 · 1 mark · Enzymes

The graph shows how enzyme activity is affected by temperature. The curve rises from a low value at 0 °C, increases to a peak at around 40 °C, then falls steeply to zero at about…

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Question 8 · 1 mark · Plant nutrition

Which descriptions of adaptations for photosynthesis are correct for spongy mesophyll tissue? air spaces for efficient gas exchange long, rectangular cells to absorb light --- ---…

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Question 9 · 1 mark · Human nutrition

The table shows the recommended daily allowance (RDA) of some nutrients for young children. The table also shows the masses of these nutrients eaten by a child in one day. mass of…

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Question 10 · 1 mark · Human nutrition

Which term is used for the uptake and use of nutrients by cells? A absorption B assimilation C egestion D ingestion

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Question 11 · 1 mark · Human nutrition

What is the function of trypsin in digestion? A It catalyses the breakdown of maltose in the mouth. B It catalyses the breakdown of maltose in the small intestine. C It catalyses…

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Question 12 · 1 mark · Human nutrition

The diagram shows the structure of a villus. Four labels point to different parts: A points to the outer epithelium near the top, B and C point to vessels inside the villus, and D…

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Question 13 · 1 mark · Transport in plants

Which graph shows the effect of humidity in the air on the rate of transpiration in a plant? Four graphs plot rate of transpiration (y-axis) against percentage humidity (x-axis,…

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Question 14 · 1 mark · Transport in plants

In some countries, spring is the time of year when daffodil plants have green leaves and produce flowers. Which parts of the daffodil plants act as sources and sinks in spring?…

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Question 15 · 1 mark · Transport in animals

In a fish, what is the sequence of structures that blood passes through after it leaves the heart? A gills → muscles → heart B gills → heart → muscles → heart C muscles → gills →…

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Question 16 · 1 mark · Diseases and immunity

The diagram shows what happens in the body during active immunity. pathogens enter the body → W are detected → lymphocytes become active, leading to three outcomes: X destroy…

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Question 17 · 1 mark · Diseases and immunity

Cholera is a disease caused by a bacterium called Vibrio cholerae which produces a toxin in the infected person's gut. What is the effect of this toxin? A The toxin causes loss of…

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Question 18 · 1 mark · Gas exchange in humans

The graph shows how the volume of air in lungs changes when a person is breathing at rest. The trace is a smooth wave of repeated breaths; point X is marked at a peak (maximum…

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Question 19 · 1 mark · Respiration

The processes listed occur in living organisms. 1 cell division 2 diffusion 3 muscle contraction 4 osmosis Which processes require energy from respiration? A 1, 2, 3 and 4 B 1 and…

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Question 20 · 1 mark · Excretion in humans

What is a role of the glomerulus? A assembling amino acids into proteins B filtration of water, glucose, urea and ions from the blood C reabsorption of glucose, ions and water…

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Question 21 · 1 mark · Coordination and response

The diagram shows a synapse between neurone 1 and neurone 2. Labels point to different structures: P points to a small sac in the end of neurone 1; Q points to particles released…

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Question 22 · 1 mark · Coordination and response

Which row shows the function of rod cells? night vision colour vision --- --- --- A yes yes B yes no C no yes D no no

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Question 23 · 1 mark · Coordination and response

The diagram shows the positions of two endocrine glands in the human body, located on top of the kidneys (the adrenal glands). What is a response of the body to the hormone…

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Question 24 · 1 mark · Homeostasis

What is a response of the human body to overheating? A vasoconstriction of arterioles B vasoconstriction of veins C vasodilation of arterioles D vasodilation of veins

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Question 25 · 1 mark · Coordination and response

What is an example of phototropism? A the growth of a root in the direction of gravity B the growth of a shoot towards light C the release of energy from glucose using light D the…

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Question 26 · 1 mark · Drugs

Which statement describes the effect of antibiotics? A Antibiotics do not affect bacteria or viruses. B Antibiotics kill bacteria but do not affect viruses. C Antibiotics kill…

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Question 27 · 1 mark · Reproduction

The diagram shows one parent Hydra growing and releasing an offspring from the side of its body. Three stages are shown: a bud forms on the side of the parent, the bud grows into…

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Question 28 · 1 mark · Reproduction

The diagram shows the changing concentrations of some hormones involved in the menstrual cycle, plotted over days 0 to 28. Four curves are shown; one curve (W) rises to a sharp…

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Question 29 · 1 mark · Inheritance

The diagram shows the chromosomes in the nucleus of a cell that divides by mitosis. The parent nucleus contains a set of chromosomes. Which diagram shows the chromosomes in the…

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Question 30 · 1 mark · Inheritance

A farmer bred together male cattle with white hair and female cattle with red hair. All the offspring produced had roan hair (a mixture of red and white). He then repeatedly bred…

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Question 31 · 1 mark · Organisation of the organism

Phagocytes and neurones are two types of specialised cell. Which statements are correct? 1 Phagocytes and neurones express the same genes. 2 Both types of cell have the same…

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Question 32 · 1 mark · Variation and selection

The table shows some features of leaves. Which leaf is adapted to survive in hot, dry habitats? number of stomata thickness of waxy cuticle surface area of leaf --- --- --- --- A…

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Question 33 · 1 mark · Variation and selection

Which row correctly describes a type of selection? type of selection humans involved example --- --- --- --- A artificial no production of farmed animals that produce lots of milk…

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Question 34 · 1 mark · Organisms and their environment

Which statement about a pyramid of energy for a food chain is correct? A It shows how energy is lost at each trophic level. B It shows the energy stored at each trophic level. C…

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Question 35 · 1 mark · Organisms and their environment

The food web shows part of an ocean ecosystem. The producers are kelp, algae and diatom. The food web links: kelp → sea urchin; algae → mussel and clam; diatom → prawn; sea…

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Question 36 · 1 mark · Organisms and their environment

A student investigated the effect of high temperature on the production of nitrate ions in soil. Two samples of soil were taken. One sample was heated to 100 °C. All the nitrate…

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Question 37 · 1 mark · Organisms and their environment

Which letter represents the lag phase in the population graph shown? The graph plots number of individuals in the population (y-axis) against time (x-axis) as an S-shaped…

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Question 38 · 1 mark · Biodiversity and conservation

Which term describes the number of different species living in an area? A biodiversity B conservation C ecosystem D population

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Question 39 · 1 mark · Human influences on ecosystems

Which source of pollution can cause eutrophication? A carbon dioxide B methane C non-biodegradable plastic D sewage

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Question 40 · 1 mark · Biotechnology and genetic modification

Some of the processes involved in the production of insulin by genetic modification are listed. 1 cutting of bacterial plasmid DNA with restriction enzymes 2 expression in…

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