Gas exchange in humans — Paper 1 · IGCSE Biology (9-1) 0970

20 A sample of expired air is collected in a gas jar. Another gas jar contains normal atmospheric air. A lighted candle is placed inside each gas jar as shown. The time taken for each flame to go out is measured. As the candles burn they use up the oxygen available in the jar. lid air sample candle gas jar X gas jar Y The table shows the results of this experiment. time for candle flame gas jar to go out / s X 15 Y 9 What is an explanation of the difference between the results in jars X and Y? A Jar X contains atmospheric air which has more carbon dioxide. B Jar X contains expired air which has more carbon dioxide. C Jar Y contains atmospheric air which has less oxygen. D Jar Y contains expired air which has less oxygen.

1 marks

Answer: D

This question in 0970/11 May/June 2018

19 The graph shows changes in the volume of air in the lungs of a person at rest, over a period of 30 seconds. 2 volume of air in lungs 1 / dm3 0 0 30 time / s Which graph shows changes in the volume of air in the lungs of the same person immediately after they have done five minutes of vigorous exercise? A B 2 2 volume volume of air in of air in lungs 1 lungs 1 / dm3 / dm3 0 0 0 30 0 30 time / s time / s C D 2 2 volume volume of air in of air in lungs 1 lungs 1 / dm3 / dm3 0 0 0 30 0 30 time / s time / s

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2018

20 As we breathe out, … 1 … is … 2 … through the lungs. Which words correctly complete gaps 1 and 2? 1 2 A carbon dioxide excreted B carbon dioxide respired C oxygen excreted D oxygen respired

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2018

21 What is the approximate percentage of oxygen in expired air? A 0.04% B 4% C 16% D 21%

1 marks

Answer: C

This question in 0970/11 May/June 2019

22 Potted plants are left for a week in a tank of water as shown. tank water soil permeable plant pot Why do the plants die? A The roots do not have enough oxygen. B The roots do not have enough water. C The roots have too much oxygen. D The roots have too much carbon dioxide.

1 marks

Answer: A

This question in 0970/11 May/June 2019

23 The diagram shows two experiments investigating gas exchange in small aerobic crustaceans. Soda lime absorbs carbon dioxide. P Q coloured coloured liquid marker liquid marker small aerobic crustaceans wire gauze soda lime glass beads instead of soda lime Which way does the liquid marker move? P Q A left right B left stays still C right left D right stays still

1 marks

Answer: B

This question in 0970/11 May/June 2019

19 The diagram shows part of the human gas exchange system. to P Q R Which row identifies P, Q and R? P Q R A alveolus wall capillary wall vein B bronchiole alveolus wall capillary C capillary layer of moisture bronchiole D alveolus wall bronchiole capillary

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2019

18 What is the approximate percentage of oxygen contained in the air breathed out of the lungs? A 0% B 4% C 16% D 20%

1 marks

Answer: C

This question in 0970/11 May/June 2020

18 What is the site of gas exchange in humans? A nose B alveoli C bronchus D trachea

1 marks

Answer: B

This question in 0970/12 May/June 2020

20 The diagram shows the breathing system. 1 2 3 What are the labelled structures? 1 2 3 A bronchus bronchiole trachea B bronchiole bronchus trachea C trachea bronchus bronchiole D trachea diaphragm bronchus

1 marks

Answer: C

This question in 0970/12 May/June 2020

22 The diagram shows some of the structures in a human lung. Where is the carbon dioxide concentration highest? from pulmonary artery C B to pulmonary vein D A

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2020

22 The diagrams show the depth and rate of breathing in a person at 12:00 and 13:00. 12:00 13:00 0.5 dm3 volume volume 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 time / seconds time / seconds What happens to the person’s breathing between 12:00 and 13:00? depth rate of breathing of breathing A decreases decreases B decreases increases C increases decreases D increases increases

1 marks

Answer: D

This question in 0970/11 May/June 2021

5 The diagram shows some cells. cilia cytoplasm nucleus Where are these cells found? A alimentary canal B blood C bronchus D plant roots

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2021

22 Which shows the correct order of structures that air travels through when a human breathes in? A alveoli  trachea  bronchioles  bronchi B trachea  bronchi  bronchioles  alveoli C alveoli  bronchioles  bronchi  trachea D trachea  bronchioles  bronchi  alveoli

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2021

12 Which chemical is a product of photosynthesis that moves out of a green leaf through its stomata? A carbon dioxide B glucose C oxygen D water

1 marks

Answer: C

This question in 0970/11 May/June 2022

22 A person lives in a climate where the air is very dry. Which row correctly compares inspired air with expired air for this person? inspired air expired air A higher carbon dioxide concentration higher oxygen concentration B lower water vapour concentration higher carbon dioxide concentration C lower oxygen concentration higher water vapour concentration D lower carbon dioxide concentration lower water vapour concentration

1 marks

Answer: B

This question in 0970/11 May/June 2022

7 By which process does oxygen move from a region of higher concentration in the alveoli to a region of lower concentration in the blood? A osmosis B breathing C diffusion D active transport

1 marks

Answer: C

This question in 0970/12 May/June 2022

22 What is the approximate percentage of oxygen in expired air? A 0.04% B 4% C 16% D 21%

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2022

22 What is the pathway of expired air as it travels out of the body? A alveoli → trachea → bronchiole → bronchi B alveoli → bronchiole → bronchi → trachea C trachea → alveoli → bronchiole → bronchi D trachea → bronchi → bronchiole → alveoli

1 marks

Answer: B

This question in 0970/11 May/June 2023

21 What are features of gas exchange surfaces in animals? A thick-walled and large surface area B thick-walled and small surface area C thin-walled and small surface area D thin-walled and large surface area

1 marks

Answer: D

This question in 0970/12 May/June 2023

22 Which chemical can be used to show the presence of carbon dioxide gas? A Benedict’s solution B biuret solution C ethanol D limewater

1 marks

Answer: D

This question in 0970/12 May/June 2023

23 The diagram represents the exchange of gases during breathing and during respiration in the body. oxygen oxygen in blood X Y carbon carbon dioxide dioxide in blood What is represented by X? A heart B kidneys C liver D lungs

1 marks

Answer: D

This question in 0970/12 May/June 2023

21 What is the composition of expired air compared with inspired air? carbon dioxide oxygen water vapour A decreased increased increased B decreased decreased increased C increased decreased decreased D increased decreased increased

1 marks

Answer: D

This question in 0970/12 Oct/Nov 2023

22 The diagram shows the human breathing system. 1 2 3 What are the labelled structures? 1 2 3 A bronchus bronchiole trachea B bronchiole bronchus trachea C trachea bronchus bronchiole D trachea diaphragm bronchus

1 marks

Answer: C

This question in 0970/12 Oct/Nov 2023

39 A student investigated gas exchange using the apparatus shown. mouthpiece limewater tube X tube Y What would be the appearance of the limewater in tube X and tube Y after breathing in and out of the mouthpiece for one minute? tube X tube Y A clear clear B clear cloudy C cloudy clear D cloudy cloudy

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2023

7 The diagram shows a section through an alveolus and through a capillary. wall of the alveolus air red capillary blood cells wall capillary X Y low carbon dioxide NOT TO concentration SCALE high carbon dioxide concentration How does carbon dioxide move from Y to X? A by active transport B by diffusion C by osmosis D by transpiration

1 marks

Answer: B

This question in 0970/11 May/June 2024

25 The diagram shows the breathing system. Which structure is the diaphragm? A B D C

1 marks

Answer: C

This question in 0970/11 May/June 2024

13 The diagram shows a cross-section of part of a leaf. Which cell controls the rate of gas exchange? D A C B

1 marks

Answer: B

This question in 0970/12 May/June 2024

7 A frog is an animal. The skin of a frog is permeable to oxygen and carbon dioxide. Which directions will have a net diffusion of oxygen and carbon dioxide when a frog swims in pond water? from the frog from the water into the water into the frog A carbon dioxide oxygen B carbon dioxide and oxygen no movement C oxygen carbon dioxide D no movement carbon dioxide and oxygen

1 marks

Answer: A

This question in 0970/12 Oct/Nov 2024

25 Which row matches a gas in expired air with a substance that can be used to test for the presence of that gas? gas present in test substance expired air A carbon dioxide DCPIP B carbon dioxide limewater C oxygen DCPIP D oxygen limewater

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2024

20 Which statements describe the difference between the composition of inspired air and expired air? 1 The percentage of carbon dioxide in inspired air is greater than in expired air. 2 The percentage of carbon dioxide in inspired air is less than in expired air. 3 The percentage of oxygen in inspired air is greater than in expired air. 4 The percentage of oxygen in inspired air is less than in expired air. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

1 marks

Answer: C

This question in 0970/11 May/June 2025

20 Which substance can be used to test for carbon dioxide? A DCPIP B ethanol C iodine solution D limewater

1 marks

Answer: D

This question in 0970/12 May/June 2025

16 Which row shows how the composition of expired air differs from inspired air? carbon dioxide oxygen concentration concentration A higher higher B higher lower C lower higher D lower lower

1 marks

Answer: B

This question in 0970/12 Oct/Nov 2025