IGCSE Biology 0610/32 October/November 2025 Past Paper with Answers

Question 1

Five organisms each have an internal skeleton made of bones, and all of them move, feed on other organisms and respire. To which kingdom do these organisms belong?

1. the animal kingdom
2. the plant kingdom
3. the fungus kingdom
4. the bacteria (prokaryote) kingdom

Question 2

Five organisms each clearly show a backbone (vertebral column) running along the body. What is the name of the group of animals that share this common feature?

1. vertebrates
2. invertebrates
3. arthropods
4. mammals

Question 3

One of the vertebrates is a fish. Which visible skeletal feature would identify an organism as a fish?

1. the bones of fins used for swimming
2. the bones of two pairs of walking legs
3. the bones of feathered wings
4. a bony external shell covering the body

Question 4 · Answer A

Step 1: Mammals have hair or fur covering the body and mammary glands that produce milk to feed their young. Step 2: They also have external ears (pinnae), sweat glands and different types of teeth. Step 3: Feathers belong to birds, gills and scales to fish, and dry scales to reptiles, so the mammal features are hair or fur and mammary glands.

Question 5 · Answer A

Step 1: The curved bones that form a cage around the chest to protect the heart and lungs are the ribs. Step 2: The skull protects the brain and the backbone runs along the body. Step 3: Limb bones support the legs or arms, so the curved chest bone labelled P is a rib.

Question 6 · Answer A

Step 1: A binomial scientific name has two parts: the genus name first, then the species name. Step 2: In Phasianus colchicus, Phasianus is the genus name and colchicus is the species name. Step 3: The full name together is the binomial and animal is a kingdom, so the species name is colchicus.

Question 7 · Answer A

Step 1: A species is a group of organisms of the same type with very similar features. Step 2: Members of a species can reproduce together to produce offspring. Step 3: Importantly, those offspring are fertile (can themselves reproduce), so a species is a group that breeds to give fertile offspring, not just organisms sharing a habitat or genus.

Question 8 · Answer A

Step 1: If a solution has the same concentration as blood plasma, there is no net movement of water by osmosis. Step 2: With no net water movement the red blood cells keep their normal shape, which happens in solution B. Step 3: The shrunken cells in A lost water (higher salt) and the swollen cells in C gained water (lower salt), so solution B matches the plasma.

Question 9 · Answer A

Step 1: Cells swell when the outside solution is more dilute (lower salt), which happens in solution C. Step 2: Cells keep their normal shape when the concentration matches, which is solution B. Step 3: Cells shrink when the outside solution is more concentrated (higher salt), which is solution A, so the order of increasing salt is C, B, A.

Question 10 · Answer A

Step 1: Blood plasma is mostly water and carries many dissolved substances around the body. Step 2: These include nutrients such as glucose and amino acids, the waste product urea, hormones and ions. Step 3: Bone is not transported in plasma, haemoglobin is inside red cells, and starch and large fat droplets are not dissolved in plasma, so the plasma carries glucose and urea.

Question 11 · Answer A

Step 1: Distilled water is more dilute than the cell contents, so water enters the plant cell by osmosis. Step 2: The vacuole fills and the cell becomes swollen and firm (turgid). Step 3: The strong cell wall stops the cell bursting, so the membrane is pushed tightly against the wall rather than the cell shrinking or bursting.

Question 12 · Answer A

Step 1: Both diffusion and osmosis happen in all living cells and both involve the random movement of particles, so the first two statements are true for both. Step 2: Osmosis is the movement of water across a partially permeable membrane, so that statement is true for osmosis only. Step 3: Ions (not water) move down a concentration gradient by diffusion, so that statement is true for diffusion only.

Question 13 · Answer A

Step 1: Some particles are moved across the membrane using energy released by respiration. Step 2: This energy-requiring movement, often against the concentration gradient, is active transport. Step 3: Diffusion and osmosis are passive and need no energy, and evaporation is a change of state, so the process is active transport.

Question 14 · Answer A

Step 1: A healthy leaf carries out photosynthesis to make food, using chlorophyll to absorb light. Step 2: A leaf badly damaged by a pathogen loses chlorophyll and cannot photosynthesise properly. Step 3: Combustion, digestion in a stomach, fertilisation and filtration of blood are not leaf processes, so the lost processes are photosynthesis and chlorophyll production.

Question 15 · Answer A

Step 1: Pathogens are disease-causing organisms or agents. Step 2: The main types are bacteria, viruses and fungi. Step 3: Red blood cells, enzymes, hormones and blood vessels are normal parts of the body, not pathogens, so two types of pathogen are bacteria and viruses.

Question 16 · Answer A

Step 1: Pathogens can spread directly when one tree touches another, for example when branches or roots are in contact. Step 2: They can also be carried indirectly by animals such as insects, or by wind, water or soil. Step 3: Photosynthesis, transpiration, active transport, osmosis and antibody production are normal processes, not ways of spreading pathogens, so transmission is by contact and by insects.

Question 17 · Answer A

Step 1: Forests are often cleared so the land can be used for farming and growing crops. Step 2: Trees are also cut down to harvest timber and to clear land for building houses, factories and roads. Step 3: Planting forests and protecting habitats reduce deforestation, and natural cycles are not causes, so the three causes are farming, timber and building.

Question 18 · Answer A

Step 1: The values show the area removed fell from about 27 thousand km2 in 2004 to about 5 thousand km2 in 2013. Step 2: After 2013 the area removed rose again towards 2022 but stayed well below the 2004 figure. Step 3: So overall the area removed decreased from 2004, with a fall to a minimum in 2013 followed by a partial rise.

Question 19 · Answer A

Step 1: Biodiversity is a measure of the variety of living things. Step 2: It is described as the number of different species found in an area. Step 3: It is not the count of one species, the mass of one organism, or the number of factories, so biodiversity is the number of different species in an area.

Question 20 · Answer A

Step 1: Removing trees destroys the habitats that animals and plants depend on. Step 2: Tree roots no longer hold the soil, so soil is eroded and washed away, and flooding can increase. Step 3: Fewer trees means less carbon dioxide is removed by photosynthesis, so atmospheric carbon dioxide rises and adds to global warming.

Question 21 · Answer A

Step 1: The muscular tube at the bottom leading to the outside is the vagina, which is F. Step 2: The narrow tube carrying an egg from an ovary towards the uterus is an oviduct, which is D. Step 3: The small round cell released from an ovary is the egg cell, which is E, so vagina F, oviduct D, egg cell E.

Question 22 · Answer A

Step 1: Sperm swim up through the uterus and into the oviducts. Step 2: An egg released from an ovary travels along the oviduct, where it meets a sperm. Step 3: Fertilisation (the joining of a sperm and egg nucleus) normally happens in the oviduct, not in the vagina or ovary.

Question 23 · Answer A

Step 1: The female reproductive hormone is oestrogen, which is produced by the ovary. Step 2: Oestrogen controls the development of female secondary sexual characteristics at puberty. Step 3: Insulin controls blood glucose, testosterone is a male hormone, and the vagina and uterus do not make these hormones, so the ovary produces oestrogen.

Question 24 · Answer A

Step 1: The endocrine system is made of glands that release hormones into the blood. Step 2: Some hormones keep the internal environment constant, which is called homeostasis. Step 3: The pancreas produces insulin, which lowers and helps control the blood glucose concentration, so the words are glands; internal; homeostasis; insulin; glucose.

Question 25 · Answer A

Step 1: A gene is a length of DNA that codes for a feature. Step 2: Many genes exist in more than one form, and each different version is called an allele. Step 3: For pod colour the gene has a green allele (G) and a yellow allele (g), so an allele is an alternative form of a gene.

Question 26 · Answer A

Step 1: Yellow is recessive, so a yellow-podded plant must have two recessive alleles; individual 1 is gg. Step 2: Individual 2 has green pods, so it has at least one G allele. Step 3: Because individual 2 produces some yellow (gg) offspring, it must also carry a g allele, so individual 2 is Gg.

Question 27 · Answer A

Step 1: Each Gg parent produces gametes carrying G or g. Step 2: Combining the gametes gives offspring GG, Gg, Gg and gg in a Punnett square. Step 3: GG and the two Gg are green (have a G), and only gg is yellow, so the ratio is 3 green : 1 yellow.

Question 28 · Answer A

Step 1: The spongy mesophyll is a layer of cells in the middle of a leaf. Step 2: It lies below the palisade layer and contains air spaces for gas exchange. Step 3: Roots anchor the plant, flowers are for reproduction and stems support the plant, so spongy mesophyll cells are found in the leaf.

Question 29 · Answer A

Step 1: The tough outer boundary that surrounds and supports the whole plant cell is the cell wall, which is J. Step 2: The large clear space in the middle is the vacuole, which is K. Step 3: The jelly-like material holding the chloroplasts is the cytoplasm, which is L, so J cell wall, K vacuole, L cytoplasm.

Question 30 · Answer A

Step 1: The nucleus contains the genetic material (DNA), arranged as chromosomes carrying genes. Step 2: Using these instructions, the nucleus controls the activities of the cell. Step 3: Absorbing light is the chloroplast, respiration is the mitochondrion, and controlling entry and exit is the membrane, so the nucleus stores the genetic material and controls the cell.

Question 31 · Answer A

Step 1: Mitochondria are small organelles where aerobic respiration takes place. Step 2: They are spread throughout the jelly-like cytoplasm of the cell. Step 3: They are not inside the nucleus, the vacuole or the cell wall, so mitochondria are found in the cytoplasm.

Question 32 · Answer A

Step 1: Mitochondria carry out aerobic respiration inside the cell. Step 2: This process releases energy from glucose for the cell to use. Step 3: Absorbing light is the chloroplast, storing genetic material is the nucleus, and controlling entry is the membrane, so mitochondria release energy by respiration.

Question 33 · Answer A

Step 1: Spongy mesophyll cells contain chloroplasts, which absorb light energy for photosynthesis. Step 2: The cells are loosely packed, leaving air spaces between them. Step 3: These air spaces and the large surface area let carbon dioxide diffuse easily to the cells for photosynthesis, so the tissue is well adapted.

Question 34 · Answer A

Step 1: Physical (mechanical) digestion breaks food into smaller pieces, for example by the teeth, without changing the molecules. Step 2: Chemical digestion breaks down large food molecules into smaller ones. Step 3: Chemical digestion involves chemical changes and uses enzymes, so physical = smaller pieces, while chemical = food molecules, chemical changes and enzymes.

Question 35 · Answer A

Step 1: Egestion is the removal of undigested food from the body. Step 2: Undigested material forms faeces, which pass out through the anus at the end of the alimentary canal. Step 3: The stomach and small intestine digest and absorb food, and the mouth is where ingestion happens, so egestion occurs at the anus.

Question 36 · Answer A

Step 1: The hard white outer covering of the crown is enamel, which is Q. Step 2: The layer just beneath the enamel that makes up most of the tooth is dentine, which is R. Step 3: The soft pink tissue surrounding the neck of the tooth is the gum, which is S, so Q enamel, R dentine, S gum.

Question 37 · Answer A

Step 1: The pulp cavity is the soft living centre of the tooth. Step 2: It contains nerves, which detect pain and temperature, and blood vessels, which supply the living tooth. Step 3: Enamel and dentine are the hard layers around the pulp, and muscles, tendons, cartilage and bone are not inside the pulp, so the pulp contains nerves and blood vessels.

Question 38 · Answer A

Step 1: Molars are the large teeth at the back of the mouth used for grinding and chewing. Step 2: They have a broad flat top (grinding surface) and are anchored by more than one root. Step 3: Incisors are chisel-shaped for biting and canines are pointed for tearing, so a tooth with a flat grinding surface and multiple roots is a molar.