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Adaptations for gas exchange: WJEC A‑Level Biology questions

Every WJEC A-Level Biology exam question on 2.2 Adaptations for gas exchange, 2016–2025, with its mark scheme and examiner’s report.

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1,223 questions

  1. Q2(a)

    Summer 2025 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(a): Explain how an amoeba carries out gas exchange. [2]

  2. Q2(b)(i)

    Summer 2025 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(b)(i): Use the data provided to calculate the two missing values. Write your answers in Table 2.3. [2] Space for working

  3. Q2(b)(ii)

    Summer 2025 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(b)(ii): Explain why the body surface of both the flatworm and the earthworm is: I. thin; [1] II. moist. [1]

  4. Q2(b)(iii)

    Summer 2025 · AS Unit 2

    3 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(b)(iii): Lugworms spend most of their lives in U-shaped burrows in tidal areas. Some species of lugworm can reach 25 cm in length. Image 2.4A shows a lugworm in its burr

  5. Q2(c)(i)

    Summer 2025 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(c)(i): Explain why the insect cannot carry out gas exchange through the body surface and needs a tracheal system to deliver oxygen to respiring tissues. [2]

  6. Q2(c)(ii)

    Summer 2025 · AS Unit 2

    1 mark2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(c)(ii): Suggest the role of the rings of chitin in the tracheoles. [1]

  7. Q2(c)(iii)

    Summer 2025 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2025 AS Unit 2, question 2(c)(iii): Use Image 2.6 to describe the change in fluid levels in the tracheoles during flight. Explain the advantage of this to the insect. [2]

  8. Q5(a)

    Summer 2024 · AS Unit 2

    4 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(a): Use Image 5.1 and your own knowledge to explain how water is moved across the gills. [4]

  9. Q5(b)(i)

    Summer 2024 · AS Unit 2

    1 mark2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(b)(i): Use Graph 5.2 to calculate the maximum pressure change within the opercular cavity. [1] Maximum pressure change = ….. Pa

  10. Q5(b)(ii)

    Summer 2024 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(b)(ii): I. Indicate on Graph 5.2, with an arrow labelled B, a point when water will enter the buccal cavity. [1] II. Indicate on Graph 5.2, with an arrow labelled G, a

  11. Q5(c)(i)

    Summer 2024 · AS Unit 2

    1 mark2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(c)(i): State the name of the structures labelled A in Image 5.3. [1]

  12. Q5(c)(ii)

    Summer 2024 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(c)(ii): Use Image 5.3 to describe and explain one adaptation of the gills for gas exchange. [2]

  13. Q5(c)(iii)

    Summer 2024 · AS Unit 2

    3 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(c)(iii): The blood flow through the structures labelled A is in the opposite direction from the water flowing over the gills. Explain the advantage of this to the fish.

  14. Q5(d)

    Summer 2024 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2024 AS Unit 2, question 5(d): The Australian Lungfish (Neoceratodus forsteri) is one of several species of fish that have evolved simple lungs. The lungs are subdivided into numerous smaller

  15. Q4(a)(i)

    Summer 2023 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2023 AS Unit 2, question 4(a)(i): Using Image 4.1 and your own knowledge, describe and explain two adaptations of the lungs for gas exchange. [2]

  16. Q4(a)(ii)

    Summer 2023 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2023 AS Unit 2, question 4(a)(ii): Using Image 4.2, explain why the person with emphysema would have a lower oxygen saturation of haemoglobin than an adult with healthy lungs. [2]

  17. Q4(b)(i)

    Summer 2023 · AS Unit 2

    4 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2023 AS Unit 2, question 4(b)(i): Describe the process of inspiration. [4] During an investigation an adult with healthy lungs and an adult with emphysema were asked to: • breathe normally for t

  18. Q4(b)(ii)

    Summer 2023 · AS Unit 2

    4 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2023 AS Unit 2, question 4(b)(ii): Complete Table 4.5 to state two differences between the two spirometry traces in Images 4.3 and 4.4 and use the information from the fact file to explain these

  19. Q2(a)(i)

    Summer 2022 · AS Unit 2

    1 mark2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2022 AS Unit 2, question 2(a)(i): The body surface of both animals is adapted for gas exchange by being thin, moist, and permeable to gases. State one other feature of the body surface that thes

  20. Q2(a)(iii)

    Summer 2022 · AS Unit 2

    2 marks2.2 Adaptations for gas exchange
    The whole paper ↗
    Summer 2022 AS Unit 2, question 2(a)(iii): Locusts are large insects. Explain how they ensure an efficient supply of oxygen to their tissues. [2]
All 39 questions on Adaptations for gas exchange, as a list
  1. Summer 2025, AS Unit 2, Q2(a) (2 marks): Explain how an amoeba carries out gas exchange. [2]
  2. Summer 2025, AS Unit 2, Q2(b)(i) (2 marks): Use the data provided to calculate the two missing values. Write your answers in Table 2.3. [2] Space for working
  3. Summer 2025, AS Unit 2, Q2(b)(ii) (2 marks): Explain why the body surface of both the flatworm and the earthworm is: I. thin; [1] II. moist. [1]
  4. Summer 2025, AS Unit 2, Q2(b)(iii) (3 marks): Lugworms spend most of their lives in U-shaped burrows in tidal areas. Some species of lugworm can reach 25 cm in length. Image 2.4A shows a lugworm in its burr
  5. Summer 2025, AS Unit 2, Q2(c)(i) (2 marks): Explain why the insect cannot carry out gas exchange through the body surface and needs a tracheal system to deliver oxygen to respiring tissues. [2]
  6. Summer 2025, AS Unit 2, Q2(c)(ii) (1 mark): Suggest the role of the rings of chitin in the tracheoles. [1]
  7. Summer 2025, AS Unit 2, Q2(c)(iii) (2 marks): Use Image 2.6 to describe the change in fluid levels in the tracheoles during flight. Explain the advantage of this to the insect. [2]
  8. Summer 2024, AS Unit 2, Q5(a) (4 marks): Use Image 5.1 and your own knowledge to explain how water is moved across the gills. [4]
  9. Summer 2024, AS Unit 2, Q5(b)(i) (1 mark): Use Graph 5.2 to calculate the maximum pressure change within the opercular cavity. [1] Maximum pressure change = ….. Pa
  10. Summer 2024, AS Unit 2, Q5(b)(ii) (2 marks): I. Indicate on Graph 5.2, with an arrow labelled B, a point when water will enter the buccal cavity. [1] II. Indicate on Graph 5.2, with an arrow labelled G, a
  11. Summer 2024, AS Unit 2, Q5(c)(i) (1 mark): State the name of the structures labelled A in Image 5.3. [1]
  12. Summer 2024, AS Unit 2, Q5(c)(ii) (2 marks): Use Image 5.3 to describe and explain one adaptation of the gills for gas exchange. [2]
  13. Summer 2024, AS Unit 2, Q5(c)(iii) (3 marks): The blood flow through the structures labelled A is in the opposite direction from the water flowing over the gills. Explain the advantage of this to the fish.
  14. Summer 2024, AS Unit 2, Q5(d) (2 marks): The Australian Lungfish (Neoceratodus forsteri) is one of several species of fish that have evolved simple lungs. The lungs are subdivided into numerous smaller
  15. Summer 2023, AS Unit 2, Q4(a)(i) (2 marks): Using Image 4.1 and your own knowledge, describe and explain two adaptations of the lungs for gas exchange. [2]
  16. Summer 2023, AS Unit 2, Q4(a)(ii) (2 marks): Using Image 4.2, explain why the person with emphysema would have a lower oxygen saturation of haemoglobin than an adult with healthy lungs. [2]
  17. Summer 2023, AS Unit 2, Q4(b)(i) (4 marks): Describe the process of inspiration. [4] During an investigation an adult with healthy lungs and an adult with emphysema were asked to: • breathe normally for t
  18. Summer 2023, AS Unit 2, Q4(b)(ii) (4 marks): Complete Table 4.5 to state two differences between the two spirometry traces in Images 4.3 and 4.4 and use the information from the fact file to explain these
  19. Summer 2022, AS Unit 2, Q2(a)(i) (1 mark): The body surface of both animals is adapted for gas exchange by being thin, moist, and permeable to gases. State one other feature of the body surface that thes
  20. Summer 2022, AS Unit 2, Q2(a)(iii) (2 marks): Locusts are large insects. Explain how they ensure an efficient supply of oxygen to their tissues. [2]
  21. Summer 2022, AS Unit 2, Q2(b)(i) (1 mark): Suggest how parapodia are also adapted to increase the efficiency of gas exchange. [1] Graph 2.3 shows the oxygen haemoglobin dissociation curves for Lumbricus
  22. Summer 2019, AS Unit 2, Q2(a) (2 marks): Calculate the mean skin surface area of the annelid. Give your answer in standard form. [2] Surface area = mm2
  23. Summer 2019, AS Unit 2, Q2(c) (4 marks): The amphibian and the mammal possess mechanisms to ventilate their lungs. Use the information in the table and your own knowledge, to explain why the amphibian
  24. Summer 2018, AS Unit 2, Q4(a)(i) (1 mark): Identify the structures labelled X and Y in Photograph B. [1] X Y
  25. Summer 2018, AS Unit 2, Q4(a)(ii) (1 mark): Suggest the function of the gill rakers. [1]
  26. Summer 2018, AS Unit 2, Q4(a)(iii) (4 marks): Use the photographs, and your knowledge, to explain why fish suffocate when out of water. [4]
  27. Summer 2018, AS Unit 2, Q4(b) (4 marks): Gas exchange in bony fish uses the countercurrent flow mechanism, where blood flows through the capillaries of the gill lamellae in the opposite direction to wa
  28. Summer 2018, AS Unit 2, Q4(c)(i) (1 mark): Identify which graph illustrates parallel flow and which graph illustrates countercurrent flow. [1] Parallel flow Countercurrent flow
  29. Summer 2018, AS Unit 2, Q4(c)(ii) (1 mark): Clearly insert arrows on the graph which represents countercurrent flow to show the direction of blood flow and of water flow. [1]
  30. Summer 2017, AS Unit 2, Q2(a) (4 marks): These systems have a number of features in common. Complete the table below to explain the purpose of these features. [4] Feature Explanation Both systems are i
  31. Summer 2017, AS Unit 2, Q2(b)(i) (1 mark): The rings of chitin in an insect’s trachea are complete. The rings of cartilage in a mammal’s trachea are incomplete or “C-shaped”. Use the information in the p
  32. Summer 2017, AS Unit 2, Q2(b)(ii) (1 mark): Name one plant tissue that shows a similar pattern of support material to that seen in an insect’s tracheae. [1]
  33. Summer 2017, AS Unit 2, Q2(c)(i) (4 marks): During inspiration the external intercostal muscles contract raising the rib cage. This causes the outer pleural membrane to move outwards. Using the graphs, ex
  34. Summer 2017, AS Unit 2, Q2(c)(ii) (1 mark): Suggest one change that you would expect to see in these curves during strenuous exercise. [1]
  35. Summer 2016, AS Unit 2, Q1(a)(i) (1 mark): Calculate the surface area to volume ratio of the housefly. [1] Surface area to volume ratio =
  36. Summer 2016, AS Unit 2, Q1(a)(ii) (2 marks): Give one advantage and one disadvantage of the tracheal system. [2] Advantage: Disadvantage:
  37. Summer 2016, AS Unit 2, Q1(b) (3 marks): Use the table to explain why an amoeba does not need a specialised gas exchange surface or circulatory system. [3]
  38. Summer 2016, AS Unit 2, Q1(c) (2 marks): State how mammals maintain the concentration gradient at their gas exchange surface. [2]
  39. Summer 2016, AS Unit 2, Q1(d) (2 marks): Suggest why cellular demand for oxygen is lower in a fish compared to a dog of the same size. [2]

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