Cambridge IGCSE Co-ordinated Sciences 0654/32 is the May/June 2026 Paper 3 (Core Theory), variant 2. It lasts 2 hours, is worth 120 marks and is sat by every Core candidate. It had twelve compulsory questions: four biology, four chemistry and four physics, each science worth 40 marks. The biggest questions, at 12 marks each, were on root hair cells and on ethene. This guide goes through the paper question by question and shows what the official mark scheme gave marks for. The paper and its mark scheme are free on the Tutopiya Learning Portal.

For an overview of all six 0654 papers from this series, see IGCSE Co-ordinated Sciences 0654 May/June 2026 past papers: what came up and how it was marked.

0654/32 at a glance

Question	Science	Topic	Marks	Main command word
1	Biology	Root hair cells: magnification, osmosis, adaptations, chlorophyll, starch test on a variegated leaf	12	Calculate, describe, complete
2	Biology	Condoms and STIs, HIV, fertilisation, the ovaries and uterus before fertilisation	8	Describe
3	Biology	A food web: ecosystems, consumers, feeding, energy flow, burning the grass	10	Describe, suggest
4	Biology	Allele, genotype and phenotype, inheritance of sex, a beta thalassaemia pedigree	10	Describe, complete, explain
5	Chemistry	The reactivity series, reacting masses, limewater, forming a calcium ion	9	State
6	Chemistry	Air, protons, neutrons and electrons in oxygen, a redox reaction, ionic compounds	11	Complete, determine
7	Chemistry	Ethene: atoms, Mr, unsaturated hydrocarbons, bromine test, poly(ethene), gas particles	12	Describe, calculate
8	Chemistry	Sulfur dioxide from fossil fuels, acid rain and pH, balancing an equation, purity of water	8	State, describe
9	Physics	Resultant force, background radiation, alpha particles, the Sun’s life cycle, light and sound from the Sun	10	Calculate, state
10	Physics	Balanced forces, a parallel lamp circuit with a fuse, static charge, warming air	8	Complete (circuit diagram)
11	Physics	A drone: battery energy, work done, power, gravitational potential energy, a speed-time graph	11	Calculate, show that
12	Physics	Ultrasound and infrasound, frequency, pressure under an elephant, evaporation and cooling	11	State, calculate
		Total	120

Question-by-question walkthrough

Question 1: root hair cells and leaves (12 marks, biology)

The question opened with a magnified drawing of a single specialised plant cell with a long extension.

• Identify the cell (1 mark): a root hair cell. “Root” on its own was ignored.
• Magnification (2 marks): image size ÷ actual size = 100 ÷ 1.3 = 77 (76.9 accepted). Units were ignored, since magnification has none.
• How plants make new cells (1 mark): cell division of existing cells; mitosis was accepted. Meiosis was rejected, and vague answers such as “multiplication” or “reproduction of cells” were ignored.
• Water entry sentence (2 marks): water moves in by osmosis through the partially permeable membrane.
• Adaptation (2 marks): a large surface area, which increases the uptake of water or mineral ions. Many mitochondria to release energy for active transport was an alternative valid point. “Long roots”, “long shape” and “a large vacuole to store water” scored nothing.
• Green pigment and its structure (2 marks): chlorophyll in the chloroplast. Writing both on one answer line was rejected, so put each on its own line.
• Starch test on a variegated leaf (2 marks): the part with no green pigment stays brown (yellow or orange accepted, red rejected) and has no starch; the green part turns blue-black (black or dark blue accepted, purple rejected) and has starch. Two or three correct cells earned 1 mark; all four earned 2.

Question 2: STIs, HIV and fertilisation (8 marks, biology)

• The condom sentence (1 mark): it protects against sexually transmitted infections.
• Group HIV belongs to (1 mark): virus. Circling more than one option scored zero.
• Two other ways HIV spreads (2 marks): from an infected mother to her baby during pregnancy, and through an infected blood transfusion. The tick boxes were penalised for over-ticking: three ticks with two correct scored 1, and four or more ticks scored 0.
• Fertilisation (2 marks, any two): the sperm and egg fuse, their nuclei fuse, and it happens in the oviduct (fallopian tube accepted). “Meets” or “mixes” was ignored, and giving more than one location was rejected.
• Ovaries and uterus before fertilisation (2 marks, any two): ovulation (an egg released from the ovary), and the lining of the uterus thickening or becoming spongy and better supplied with blood. The word lining mattered: “uterus wall” on its own was ignored. Oestrogen released by the ovaries was given as an alternative valid point.

Question 3: a food web (10 marks, biology)

The food web linked grass, locust, impala, scorpion, baboon and leopard.

• Ecosystem sentence (2 marks): an ecosystem is the community of organisms and their environment, interacting together.
• A carnivore and a tertiary consumer (2 marks): leopard or scorpion (baboon also accepted) for the carnivore; baboon for the tertiary consumer, as it sits fourth in the chain grass → locust → scorpion → baboon.
• The locust-to-scorpion arrow (1 mark): feeding. Circling more than one answer scored zero.
• Energy flow through the impala chain (3 marks, any three): energy comes from the Sun; grass is the producer; light energy becomes chemical energy in the grass; energy passes from grass to impala and from impala to leopard; and some energy is lost to the environment. One example of loss, such as respiration or only about 10% being passed on, was accepted, but “energy used up” was ignored.
• Burning the grass (2 marks, any two): less food for primary consumers and smaller populations of them, knock-on effects higher up the food chains, loss of habitat, loss of biodiversity, and soil loss or flooding. Global effects such as climate change were ignored, as was “pollution” without detail.

Question 4: inheritance (10 marks, biology)

• Matching words to definitions (2 marks): allele is an alternative form of a gene, genotype is the genetic make-up, phenotype is the observable features. One or two correct lines scored 1; drawing more than one line from a box was rejected.
• Meaning of inheritance (2 marks): the transmission of genetic information from generation to generation (passing genes or alleles to offspring was accepted).
• Sex chromosome table (2 marks): female gamete X, male gamete X or Y, female zygote X and X, male zygote X and Y. Two or three rows correct scored 1.
• Males with beta thalassaemia in the pedigree (1 mark): 2.
• Homozygous (1 mark): two identical alleles of a gene. “Two recessive alleles” alone was ignored, because it describes one example rather than the meaning.
• Why low haemoglobin causes tiredness (2 marks): haemoglobin is needed to carry oxygen, so less (aerobic) respiration takes place. “No oxygen” was ignored; say less oxygen.

Question 5: the reactivity series (9 marks, chemistry)

Every answer in part (a) had to be chosen from the list of metals printed on the paper.

• Five one-mark recall parts (5 marks): brass is copper and zinc; calcium and magnesium are in Group II; aluminium is extracted by electrolysis (potassium, sodium, calcium or magnesium also accepted); potassium and sodium are alkali metals; and iron or copper acts as a catalyst (zinc, silver or gold also accepted). The two-metal parts needed both metals for the mark.
• Reacting mass (1 mark): 5.0 g of calcium reacts with 2.0 g of oxygen, and 40.0 g is eight times as much calcium, so 16 g of oxygen.
• Gas that turns limewater milky (1 mark): carbon dioxide.
• Forming Ca²⁺ (2 marks): the atom loses electrons, and it loses two. Any answer about sharing electrons was rejected for both marks.

Question 6: air, atoms and redox (11 marks, chemistry)

• Air sentences (4 marks): air is a mixture; 78% is nitrogen; the noble gas is argon; the polluting gas is methane.
• Oxygen atom, proton number 8 and mass number 16 (3 marks): 8 neutrons, 8 electrons, electronic configuration 2,6 (a correct shell diagram was accepted).
• Word equation (1 mark): magnesium + copper oxide → magnesium oxide + copper.
• Why it is redox (1 mark): oxidation and reduction happen together: magnesium gains oxygen and copper oxide loses it. “Oxygen moves from copper to magnesium” was ignored.
• Two other properties of ionic compounds (2 marks): high melting or boiling points; conduct electricity when molten or in solution but not when solid. Being solid at room temperature and being brittle were also credited. Solubility was ignored, because the question had already given it.

Question 7: ethene (12 marks, chemistry)

• Atoms in C₂H₄ (1 mark): 6.
• Relative molecular mass (2 marks): (2 × 12) + (4 × 1) = 28.
• Unsaturated and hydrocarbon (3 marks): unsaturated means it contains a C=C double bond; a hydrocarbon contains carbon and hydrogen, and only carbon and hydrogen (the third mark). Points only scored under the correct heading.
• Test for unsaturation (2 marks): add bromine water; it turns from orange to colourless. “Clear” was ignored, so write colourless.
• The polymer (1 mark): poly(ethene), with polyethene or polythene accepted.
• Type of polymerisation (1 mark): addition.
• Gas particles (2 marks): the motion is rapid and random; the particles are widely separated. “Moves freely”, “not touching” and “more space” were ignored.

Question 8: sulfur dioxide, acid rain and water (8 marks, chemistry)

• Solid fossil fuel (1 mark): coal.
• Why sulfur dioxide forms (1 mark): the fuel contains sulfur or sulfur compounds.
• pH of acid rain (1 mark): any value from 4 to 6; “below 7” was also accepted.
• Another way to measure pH (2 marks): use universal indicator and compare the colour with a pH chart. “pH paper” on its own was ignored.
• Balancing the equation (2 marks): 2H₂ + O₂ → 2H₂O, one mark for each 2.
• Why the water is impure (1 mark): pure water boils at 100 °C, so a boiling point of 101 to 102 °C shows impurities. Saying only that it boils over a range was ignored. The mark needed the link to 100 °C.

Question 9: a spacecraft, radiation and the Sun (10 marks, physics)

• Resultant force (1 mark): 30 000 000 − 24 000 000 = 6 000 000 N upwards.
• Another source of background radiation (1 mark): radon gas, rocks, buildings, food and drink, soil, nuclear accidents or medical sources. Non-ionising examples such as UV were rejected.
• An effect of ionising radiation (1 mark): cancer, cell death or mutations (damage to cells or DNA accepted). “Affects DNA” or “burns” unqualified was ignored.
• The alpha particle (1 mark): it is the nucleus of a helium atom.
• The Sun’s next stages (2 marks): one mark for naming red giant or white dwarf, and the second for putting them in order: red giant, then white dwarf. Adding a wrong stage was rejected for the second mark, although “red supergiant” and a black dwarf after the white dwarf were ignored.
• Why sound cannot reach Earth (1 mark): sound needs a medium and cannot travel through the vacuum of space. “There is no air in space” on its own was ignored, so link it to sound needing particles to travel.
• Distance to the Sun (2 marks): distance = speed × time = 3.0 × 10⁵ × 500 = 150 000 000 km (1.5 × 10⁸ km).
• Visible light on the spectrum (1 mark): in the middle box of the seven, between ultraviolet and infrared.

Question 10: a motorcycle (8 marks, physics)

• Constant speed (1 mark): the horizontal forces are balanced, so the air resistance equals the driving force. “In equilibrium” or “cancel out” was ignored.
• Drawing the circuit (4 marks): correct symbols for the fuse, lamps and switches; the two lamps in parallel; each switch placed to control its own lamp; and the fuse in series with the battery. A series circuit lost the parallel and switch marks, and a wrong symbol for a component blocked the marks that depended on it.
• How a fuse works (1 mark): it melts when the current is too high and breaks the circuit.
• Particles transferred by friction (1 mark): electrons. Naming any other particle, or a “positively charged electron”, was rejected.
• Warming air in the tyres (1 mark): the particles move faster (gain kinetic energy). “Vibrate faster” and “more energetic” were ignored.

Question 11: a drone (11 marks, physics)

• Energy from the battery (3 marks): convert first: 12 mA = 0.012 A and 1 hour = 3600 s. Then E = IVt = 14.8 × 0.012 × 3600 = 640 J (639.36 J). The conversions earned the first mark. An answer that used IVt correctly but with a wrong conversion (for example 177.6 J from 14.8 × 12 × 1) could still earn credit through error carried forward, so always write the formula and your working.
• Show that the work done is about 590 J (2 marks): weight = mg and work = force × distance (or Ep = mgh), then 4.0 × 9.8 × 15 = 588 J. As a “show that”, the substitution had to be written down.
• Useful power (2 marks): P = work ÷ time = 590 ÷ 3.0 = 197 W (196 W from using 588 J).
• The energy store that increases (1 mark): gravitational potential energy. “Gravity” or “gravitational force” was ignored.
• Maximum speed from the graph (1 mark): 5 m/s.
• Show that the distance is 50 m (2 marks): the distance is the area under the graph, a triangle: ½ × 20 × 5 = 50 m.

Question 12: bats and elephants (11 marks, physics)

• Ultrasound (1 mark): sound with a frequency above 20 kHz (20 000 Hz).
• Frequency (1 mark): the number of waves passing a point per second. “Pitch” and “number of peaks per second” were ignored.
• A frequency for infrasound (2 marks): any value below 20 Hz, explained by the human audible range starting at 20 Hz. 20 Hz itself was ignored, because it is the limit, not below it.
• Pressure under the elephant (3 marks): total area = 4 × 0.13 = 0.52 m²; pressure = force ÷ area = 35 000 ÷ 0.52 = 67 000 N/m² (67 308 accepted). Using one foot’s area, 35 000 ÷ 0.13 = 270 000 N/m², was allowed through error carried forward.
• Evaporation sentences (3 marks): liquid to gas (vapour accepted); the more energetic particles escape from the surface. “Faster” or “active” was ignored for energetic, and “top” for surface.
• Why elephants spray water on themselves (1 mark): evaporation cools them. Cleaning or removing insects scored nothing.

Where the marks are on 0654/32

• Fill-in, circle, tick, match and drawing tasks carried 31 of the 120 marks: sentence completions, the starch and sex-chromosome tables, the HIV tick boxes, balancing an equation, placing visible light and the 4-mark circuit. These are the most reliable marks on the paper, but over-ticking and circling two answers scored zero.
• Describe questions carried 27 marks, from fertilisation and energy flow to the bromine test and the Sun’s life cycle. Most were marked “any two” or “any three”, so separate points score.
• “State”, “name” and “identify” carried 26 marks. Question 5(a) alone gave five marks for picking metals from a printed list.
• Calculations, “determine” and “show that” carried 25 marks, spread across all three sciences: magnification, reacting masses, Mr, atomic structure, resultant force, the distance to the Sun, the drone’s energy, work and power, area under a graph and pressure.
• Suggest (6 marks) and explain (5 marks) carried 11 marks together. These were short: burning grass, infrasound, the cooling effect of evaporation, low haemoglobin, redox and balanced forces.
• Questions 1 and 7 were the biggest at 12 marks each. Questions 11 and 12 together held 12 calculation marks.

How to self-mark 0654/32 with the mark scheme

1. Learn the abbreviations first. A semicolon separates marking points, a slash shows alternatives, A means accept, R means reject, I means ignore, ecf means error carried forward and AVP means any other valid point. An underlined word, such as “alleles” in 4(c)(ii), must appear in your answer.
2. Check the instructions on choice questions. In 2(b)(ii) extra ticks cost marks, in 2(b)(i) and 3(c) circling more than one answer scored zero, and in 1(e) writing both answers on one line was rejected.
3. Mark calculations step by step. A correct final answer with the unit scores full marks. If your answer is wrong, look for the method mark (for example, the 0.012 A and 3600 s conversions in 11(a)) and any ecf, such as using one foot’s area in 12(b).
4. For “show that” questions, check your working. In 11(b)(i) and 11(c)(ii) the answer is given, so the marks are for the substitution and the calculation you wrote down.
5. Read the guidance column for rejected words, such as purple for the starch test, meiosis in 1(b)(ii), sharing electrons in 5(d) and “clear” for bromine water.
6. Log each lost mark as missing knowledge, a misread command word or a careless slip, and revise in that order.

Sit 0654/32 as a timed mock

The paper allows 120 minutes for 120 marks, one minute per mark. A workable plan:

Block	Marks	Time
Question 1	12	12 minutes
Question 2	8	8 minutes
Question 3	10	10 minutes
Question 4	10	10 minutes
Question 5	9	8 minutes
Question 6	11	10 minutes
Question 7	12	11 minutes
Question 8	8	7 minutes
Question 9	10	10 minutes
Question 10	8	8 minutes
Question 11	11	11 minutes
Question 12	11	10 minutes
Check, especially unit conversions and calculations	–	5 minutes

The chemistry recall questions (5 and 8) can be done slightly faster, which buys time for the physics calculations and the circuit drawing.

Other May/June 2026 0654 papers

• 0654 Paper 12 (Core Multiple Choice)
• 0654 Paper 22 (Extended Multiple Choice)
• 0654 Paper 42 (Extended Theory)
• 0654 Paper 52 (Practical Test)
• 0654 Paper 62 (Alternative to Practical)

Practise and download

• Download 0654/32 and its mark scheme on the Learning Portal →
• All 0654 May/June 2026 papers: overview and marking patterns
• Try a free IGCSE Co-ordinated Sciences quiz

Need help with a 0654 topic? Book a free trial lesson with an IGCSE Co-ordinated Sciences tutor →

Frequently asked questions

What topics were on 0654 Paper 32 May/June 2026? +

Twelve questions, four per science. Biology: root hair cells and a starch test, condoms and HIV, a food web, and inheritance with a beta thalassaemia pedigree. Chemistry: the reactivity series, air and atomic structure, ethene, and sulfur dioxide and acid rain. Physics: a spacecraft and the Sun, a motorcycle circuit, a drone's energy and motion, and bats, elephants and pressure.

How many marks is 0654/32 and how long is it? +

It is out of 120 marks and lasts 2 hours. Biology (Questions 1 to 4), chemistry (5 to 8) and physics (9 to 12) are worth 40 marks each. Question 1, on root hair cells, is the biggest single question at 12 marks, level with Question 7 on ethene.

What was the answer to the drone energy calculation in 0654/32? +

Question 11(a) gave 14.8 V, 12 mA and 1 hour. Converting to 0.012 A and 3600 s, energy = 14.8 × 0.012 × 3600 = 640 J (639.36 J). It was worth 3 marks, one of them for the unit conversions.

What was the pressure under the elephant in 0654/32? +

The four feet have a total area of 4 × 0.13 = 0.52 m², so pressure = 35 000 ÷ 0.52 = 67 000 N/m². Using only one foot's area (270 000 N/m²) could still earn credit through error carried forward.

Is 0654/32 the Core or Extended paper? +

Core. Paper 3 is the Core theory paper, sat alongside Paper 1 (Core multiple choice) and either Paper 5 or Paper 6. Extended candidates sit Paper 4 instead.

Where can I download 0654/32 May/June 2026 and its mark scheme? +

Both are free to download and print on the Tutopiya Learning Portal, on the Cambridge IGCSE Co-ordinated Sciences 0654 past papers page.

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