Cambridge IGCSE Biology (9-1) 0970 — 2024 Oct/Nov Paper 3 · Variant 2

This document has 16 pages. [Turn over Cambridge IGCSE™(9–1) BIOLOGY 0970/32 Paper 3 Theory (Core) October/November 2024 1 hour 15 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 80. ● The number of marks for each question or part question is shown in brackets [ ]. DC (PQ) 347697 © UCLES 2024 * 3 0 3 8 9 2 5 4 5 8 * ,










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2 0970/32/O/N/24 © UCLES 2024 1 (a) Fig. 1.1 is a photomicrograph showing a cross‑section of an artery. Fig. 1.1 On Fig. 1.1, identify and label the: • artery wall • lumen. [2] (b) Complete the table by circling the correct words to show the differences between arteries and veins. type of blood vessel relative thickness of the wall relative diameter of the lumen artery thick / thin wide / narrow vein thick / thin wide / narrow [2] (c) State the name of the structures in veins that ensure one‑way flow of blood. … [1] * 0000800000002 * ,










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3 0970/32/O/N/24 © UCLES 2024 [Turn over (d) Fig. 1.2 is a simplified diagram of the circulatory system in humans. organ A pulmonary vein aorta pulmonary artery vena cava renal vein renal artery organ B organ C other organs Fig. 1.2 (i) State the names of the organs represented by the letters A, B and C in Fig. 1.2. A … B … C … [3] (ii) Draw two arrows on Fig. 1.2 to show the direction of blood flow in the pulmonary vein and the pulmonary artery. [1] (e) State the name of the blood vessels that transfer substances to and from cells. … [1] (f) Circle the names of two waste substances that are transferred from cells to blood. amino acids carbon dioxide fatty acids glucose oxygen urea [2] [Total: 12] * 0000800000003 * ,










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4 0970/32/O/N/24 © UCLES 2024 2 (a) Tick (✓) all the boxes that describe enzymes. they are permanently changed by the reaction they are involved in all metabolic reactions they are proteins they are solvents they slow down all chemical reactions [2] (b) Fig. 2.1 shows the effect of pH on the activity of three different digestive enzymes, X, Y and Z. 0 1 2 3 4 5 6 pH enzyme activity X Y Z 7 8 9 10 11 12 Fig. 2.1 Using the information in Fig. 2.1: (i) State the optimum pH of enzyme Z. … [1] * 0000800000004 * ,










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5 0970/32/O/N/24 © UCLES 2024 [Turn over (ii) State a pH value at which both enzymes X and Y are active. … [1] (iii) State a pH value at which enzyme Y is completely denatured. … [1] (iv) Enzyme X is a protease. Describe its location and action in the digestive system. location … action … [2] (v) Enzyme Y is produced by the salivary glands. State the substrate and product of enzyme Y. substrate … product … [2] (c) State the type of digestion that uses enzymes. … [1] (d) State one factor, other than pH, that affects enzyme activity. … [1] [Total: 11] * 0000800000005 * ,










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6 0970/32/O/N/24 © UCLES 2024 3 (a) Fig. 3.1 is a diagram of part of the carbon cycle. Three processes that occur in the carbon cycle are labelled Q, R and S. Q S R carbon in the atmosphere carbon in dead organisms carbon in fossil fuels carbon in plants carbon in herbivores Fig. 3.1 (i) Complete the table by stating the names of processes Q, R and S in Fig. 3.1. letter in Fig. 3.1 name of the process Q R S [3] (ii) Draw one arrow on Fig. 3.1 to represent the transfer of carbon by respiration in herbivores. [1] * 0000800000006 * ,










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7 0970/32/O/N/24 © UCLES 2024 [Turn over (b) Carbon dioxide is one gas that causes climate change. State the name of one other gas that causes climate change. … [1] (c) Suggest one way that humans can increase the rate of removal of carbon dioxide from the atmosphere. … … … [1] (d) Proteins contain carbon. State two other chemical elements all proteins contain. 1 … 2 … [2] (e) Describe what is meant by the term carnivore. … … … [1] [Total: 9] * 0000800000007 * ,










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8 0970/32/O/N/24 © UCLES 2024 4 A population of a species of fish was accidentally introduced into a lake. (a) State two features that can be used to classify this introduced species as a fish. 1 … 2 … [2] (b) Describe what is meant by the term population. … … … … … [2] (c) Fig. 4.1 shows the changes in the population size of the introduced fish species in the lake between 2004 and 2010. 2004 2005 2006 2007 year 2008 2009 2010 population size A B C Fig. 4.1 * 0000800000008 * ,










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9 0970/32/O/N/24 © UCLES 2024 [Turn over (i) The boxes on the left show the letters identifying the sections of the graph in Fig. 4.1. The boxes on the right show the phases of population growth. Draw lines to link each letter with the correct phase. Draw three lines. letter from Fig. 4.1 A B C phase death exponential (log) lag stationary [3] (ii) Describe possible reasons for the change in population size between 2009 and 2010 in Fig. 4.1. … … … … … … … [3] [Total: 10] * 0000800000009 * ,










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10 0970/32/O/N/24 © UCLES 2024 5 (a) A student investigated the effect of windspeed on the rate of transpiration. The student placed a fan at different distances from a plant shoot and measured the distance the air bubble moved in three minutes. The distance the air bubble moved can be used to calculate the rate of water uptake, which is equivalent to the rate of transpiration. Fig. 5.1 shows the apparatus the student used. ruler fan cut shoot reservoir capillary tube air bubble distance of the fan from the shoot beaker water Fig. 5.1 Table 5.1 shows their results. Table 5.1 distance of the fan from the shoot / m distance travelled by the air bubble in three minutes / mm rate of water uptake / mm per second 0.3 26 0.14 0.4 25 0.14 0.5 23 0.13 0.6 20 0.7 19 0.11 0.8 16 0.09 * 0000800000010 * ,










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11 0970/32/O/N/24 © UCLES 2024 [Turn over (i) Calculate the rate of water uptake when the fan is 0.6 m from the plant shoot. Give your answer to two decimal places. Space for working. … mm per second [2] (ii) Using the information in Fig. 5.1 and Table 5.1, complete the sentences by writing a word or phrase in the spaces to describe the results. As the fan is moved further away from the shoot, the windspeed … and the … moved by the air bubble decreased. During transpiration water evaporates from the surfaces of the … cells into the air spaces inside the leaf. The water vapour diffuses out of the leaf through the … . This causes water to move through the capillary tube causing the air bubble to move towards … . [5] (iii) State one other factor that affects the rate of transpiration. … [1] (b) State two uses of water in a plant. 1 … 2 … [2] (c) Explain why the leaf can be described as an organ. … … … … … [2] [Total: 12] * 0000800000011 * ,









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12 0970/32/O/N/24 © UCLES 2024 6 Fig. 6.1 is a photograph of intensive egg production on a chicken farm. Fig. 6.1 (a) In 1905, each chicken produced a mean of 120 eggs per year. In 2021, each chicken produced a mean of 300 eggs per year. Calculate the percentage increase in mean egg production per year. Space for working. …% [2] * 0000800000012 * ,









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13 0970/32/O/N/24 © UCLES 2024 [Turn over (b) Egg production has increased due to selective breeding and intensive farming. Describe the disadvantages of intensive livestock farming. … … … … … … … [3] (c) Complete the flowchart to describe how egg production in chickens is increased by selective breeding. identify the chickens that … use these chickens to … observe the offspring for improvement in egg production repeat this process over many … [3] (d) Selective breeding is also used to increase crop plant production. State two other ways to increase crop plant production. 1 … 2 … [2] [Total: 10] * 0000800000013 * ,









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14 0970/32/O/N/24 © UCLES 2024 7 (a) A scientist investigated the effect of the enzyme pectinase on the volume of fruit juice produced by the same mass of two different fruits. Fig. 7.1 shows the results. 0 100 200 300 400 volume of fruit juice produced / dm3 blackcurrant yellow plum type of fruit 500 600 700 800 key without pectinase with pectinase Fig. 7.1 Describe the results shown in Fig. 7.1. … … … … … … … [3] (b) State two components of a balanced diet that are provided by fruits such as blackcurrants and plums. 1 … 2 … [2] * 0000800000014 * ,









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15 0970/32/O/N/24 © UCLES 2024 [Turn over (c) State two reasons why bacteria are useful in biotechnology and genetic modification. 1 … 2 … [2] (d) The box on the left contains the beginning of a sentence. The boxes on the right show some sentence endings. Draw two lines to make two correct sentences. Genetic modification can only be done in plants. changes the genetic material of an organism. inserts, changes or removes genes. involves sexual reproduction. is used in active transport. [2] [Total: 9] * 0000800000015 * ,









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16 0970/32/O/N/24 © UCLES 2024 8 (a) Alveoli are the gas exchange surfaces in humans. (i) State two features of gas exchange surfaces in humans. 1 … 2 … [2] (ii) State the name of the organ system alveoli belong to. … [1] (b) State the word equation for aerobic respiration. … [2] (c) Explain why muscle cells have a high rate of respiration. … … … … … [2] [Total: 7] Permission to reproduce items where third‑party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. * 0000800000016 * ,









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This document consists of 12 printed pages. © Cambridge University Press & Assessment 2024 [Turn over Cambridge IGCSE™ (9–1) BIOLOGY 0970/32 Paper 3 Theory (Core) October/November 2024 MARK SCHEME Maximum Mark: 80 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the October/November 2024 series for most Cambridge IGCSE, Cambridge International A and AS Level components, and some Cambridge O Level components.

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 2 of 12 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptions for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 3 of 12 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind. Science-Specific Marking Principles 1 Examiners should consider the context and scientific use of any keywords when awarding marks. Although keywords may be present, marks should not be awarded if the keywords are used incorrectly. 2 The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for any correct statement that is contradicted within the same question part. Wrong science that is irrelevant to the question should be ignored. 3 Although spellings do not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other syllabus terms with which they may be confused (e.g. ethane / ethene, glucagon / glycogen, refraction / reflection). 4 The error carried forward (ecf) principle should be applied, where appropriate. If an incorrect answer is subsequently used in a scientifically correct way, the candidate should be awarded these subsequent marking points. Further guidance will be included in the mark scheme where necessary and any exceptions to this general principle will be noted. 5 ‘List rule’ guidance For questions that require n responses (e.g. State two reasons …): • The response should be read as continuous prose, even when numbered answer spaces are provided. • Any response marked ignore in the mark scheme should not count towards n. • Incorrect responses should not be awarded credit but will still count towards n. • Read the entire response to check for any responses that contradict those that would otherwise be credited. Credit should not be awarded for any responses that are contradicted within the rest of the response. Where two responses contradict one another, this should be treated as a single incorrect response. • Non-contradictory responses after the first n responses may be ignored even if they include incorrect science.

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 4 of 12 6 Calculation specific guidance Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show your working’. For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded by the examiner to the number of significant figures given in the mark scheme. This may not apply to measured values. For answers given in standard form (e.g. a  10n) in which the convention of restricting the value of the coefficient (a) to a value between 1 and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme. Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded. Exceptions to this general principle will be noted in the mark scheme. 7 Guidance for chemical equations Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme. State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme. Mark scheme abbreviations • ; separates marking points • / alternative responses for the same marking point • R reject the response • A accept the response • I ignore the response • ecf error carried forward • AVP any valid point • ora or reverse argument • AW alternative wording • underline actual word given must be used by candidate (grammatical variants excepted) • ( ) the word / phrase in brackets is not required but sets the context

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 5 of 12 Question Answer Marks Guidance 1(a) artery / wall, labelled ; lumen labelled ; 2 1(b) ] type of vessel relative thickness of wall relative diameter of lumen artery thick narrow vein thin wide ;; 2 one mark for each correct row 1(c) valves ; 1 1(d)(i) A lungs ; B heart ; C kidney ; 3 1(d)(ii) arrow drawn from organ B to organ A for the pulmonary artery and arrow drawn from organ A to organ B for the pulmonary vein ; 1 1(e) capillaries ; 1 1(f) carbon dioxide circled ; urea circled ; 2

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 6 of 12 Question Answer Marks Guidance 2(a) box 2: they are involved in all metabolic reactions ticked ; box 3: they are proteins ticked ; 2 2(b)(i) 9 ; 1 2(b)(ii) any value within the range 4 to 7 inclusive ; 1 2(b)(iii) any value within the range 0 to 4 or 10 to 12 inclusive ; 1 2(b)(iv) location: stomach ; action: (catalyses the) breakdown of proteins (to amino acids) ; 2 2(b)(v) substrate: starch ; product: (reducing or simple) sugar ; 2 2(c) chemical ; 1 2(d) temperature / AVP ; 1

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 7 of 12 Question Answer Marks Guidance 3(a)(i) letter in Fig. 3.1 name of the process Q photosynthesis ; R combustion ; S feeding ; 3 3(a)(ii) arrow drawn in the correct direction from ‘carbon in herbivores’ box to ‘carbon in the atmosphere’ box ; 1 3(b) methane / AVP ; 1 3(c) any one from: plant (more) trees / plants ; AVP ; 1 3(d) any two from: oxygen ; hydrogen ; nitrogen ; 2 3(e) an animal that gets it energy by eating other animals ; 1

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 8 of 12 Question Answer Marks Guidance 4(a) any two from: scales ; gills ; swim bladder ; fins ; lateral line ; AVP ; 2 4(b) (a group of organisms of) one / same, species ; living in the same area, at the same time ; 2 4(c)(i) death A exponential (log) B lag C stationary ;;; 3 one mark for each correct line 4(c)(ii) any one from: more fish died than were born / AW ; (because of:) disease ; pollution ; competition for / lack of, (named) resources or described ;; predation / hunting / (over)fishing ; introduction of new species ; AVP ;; 3 e.g. lack of, space / breeding sites / mates / oxygen e.g. destruction of habitats / natural disaster (described) / consequence of climate change e.g. raised water temperatures / drought / emigration

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 9 of 12 Question Answer Marks Guidance 5(a)(i) 0.11 ;; 2 MP1 (20 mm / (180 s)) / 0.11(111111) MP2 calculated value expressed to two decimal places ecf from previous step 5(a)(ii) decreased ; distance ; mesophyll ; stomata ; shoot / plant / left / leaf / AW ; 5 A guard cells A fan / reservoir 5(a)(iii) temperature / AVP ; 1 5(b) any two from: photosynthesis ; solvent ; transport ; support ; germination ; AVP ; 2 e.g. cooling / metabolic reactions / transpiration 5(c) (a leaf is) a group of tissues ; performing / AW,(specific) function(s) ; 2 Question Answer Marks Guidance 6(a) 150(%) ;; 2 MP1 300–120 or 180 MP2 correct calculation

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 10 of 12 Question Answer Marks Guidance 6(b) any three from: ref. to pollution / greenhouse gas emissions ; waste disposal / sewage / slurry / eutrophication (described) / AW ; animal welfare concerns / AW ; increased use / overuse, of antibiotics ; increased risk of disease / disease spreads more quickly ; AVP ;; 3 6(c) lay the most eggs / AW ; breed / cross / reproduce / mate / produce offspring / AW ; generations ; 3 6(d) any two from: insecticides / pesticides ; herbicides ; fertilisers ; agricultural machinery ; genetic modification ; AVP ; 2

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 11 of 12 Question Answer Marks Guidance 7(a) any three from: 1 with pectinase (overall) more (fruit) juice produced / without pectinase less juice produced ; 2 with pectinase yellow plum has a more juice than blackcurrants / with pectinase blackcurrants have less juice than plums ; 3 without pectinase blackcurrants have more juice than plums / without pectinase plums have less juice than blackcurrants ; 4 greatest increase in juice with pectinase in plums (than blackcurrants) / smallest increase in juice with pectinase in blackcurrants (than plums) ; 5 comparative / manipulative, data quote ; 3 7(b) any two from: (named) vitamins ; (named) mineral / ions ; water ; fibre ; (named) carbohydrate ; proteins ; 2 7(c) any two from: rapid reproduction rate ; ability to make complex molecules ; AVP ;; 2 e.g. no ethical concerns / have plasmids 7(d) genetic modification linked to: changes the genetic material of an organism ; inserts, change or removes genes ; 2

0970/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2024 © Cambridge University Press & Assessment 2024 Page 12 of 12 Question Answer Marks Guidance 8(a)(i) any two from: large surface area ; thin (surface) ; good blood supply ; good ventilation ; moist ; 2 8(a)(ii) breathing system / gas exchange system / respiratory system ; 1 8(b) glucose + oxygen ; → carbon dioxide + water ; 2 8(c) (respiration releases) energy ; needed for movement / needed for muscle contraction ; 2