AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2021: Question 5

8 marks · Standard Demand difficulty · Extended Answer

Explain the impact of deforestation and food production on atmospheric carbon dioxide levels and compare dietary carbon footprints using a bar chart.

Practise this question

Question

The image shows a multi-part GCSE science question. Part 05.1 asks for one way deforestation increases atmospheric carbon dioxide. Part 05.2 asks for another greenhouse gas besides carbon dioxide. Part 05.3 asks for two ways meat production releases carbon dioxide. Part 05.4 presents a bar chart titled Figure 4, showing the mass of carbon dioxide released in kg per person per year for three diets: 'Typical' (2000 kg), 'Diet A' (1250 kg), and 'Diet B' (250 kg). Students are asked to compare the mass of carbon dioxide released for these three diets using data from the chart.
Question text

05 Increased carbon dioxide levels in the atmosphere contribute to climate change.

05.1 Give one way deforestation can increase carbon dioxide levels in the atmosphere.

[1 mark]

05.2 Name one other gas that contributes to climate change.

Do not refer to carbon dioxide in your answer.

[1 mark]

05.3 Meat is produced for humans to eat.

Give two ways the production of meat releases carbon dioxide.

[2 marks]

05.4 The mass of carbon dioxide released during the production of food varies depending

on the type of food.

Figure 4 shows the mass of carbon dioxide released as a result of three

different diets.

Figure 4

Compare the mass of carbon dioxide released as a result of the three diets shown

in Figure 4.

Use data from Figure 4 in your answer.

[4 marks]

Mark scheme

Show the mark scheme The mark scheme provides marking points for questions 05.1 to 05.4. For 05.1, it accepts reduced photosynthesis, burning wood, or decay. For 05.2, it accepts methane or water vapour. For 05.3, it accepts animal respiration or fuel used for transport, heating, or processing. For 05.4, a level-based mark scheme is used: Level 2 (3-4 marks) requires comparing all three diets and quoting data or calculations; Level 1 (1-2 marks) requires identifying relevant features and differences. Indicative content includes specific data comparisons, such as 'Typical' diet releasing 750 kg more than 'A' and 1750 kg more than 'B'.

AO /

Question Answers Extra information Mark

Spec. Ref.

05.1 any one from: 1 AO1

• less / decreased / reduced 4.7.3.4

photosynthesis

allow burning / combustion (of

• (more) burning / combustion

fossil fuel in machinery)

(of wood)

• decomposition / decay (of

wood)

05.2 methane allow water (vapour) 1 AO1

4.7.3.5

allow other correct greenhouse

gases eg nitrous oxide(s),

nitrogen oxide, ozone,

hydrofluorocarbons,

perfluorocarbons, sulfur

hexafluoride

05.3 any two from: 2 AO2

• respiration (by animals) 4.7.3.5

• fuel burnt / used for transport ignore burning / combustion 4.7.3.4

unqualified 4.7.2.2

• fuel burnt / used to heat / light

buildings (in intensive

farming)

• fuel burnt / used to process /

cook (meat)

AO /

Question Answers Mark

Spec. Ref.

05.4 Level 2: Scientifically relevant features are identified; the way(s) in 3–4 AO3

which they are similar / different is made clear and (where 4.7.3.5

appropriate) the magnitude of the similarity / difference is noted.

Level 1: Relevant features are identified and differences noted. 1–2

No relevant content 0

Indicative content

General

• all diets cause carbon dioxide to be released

Typical diet 15

• releases more carbon dioxide than diet A and B

• releases 750 (kg per person per year) more carbon dioxide than

diet A

• releases 1750 (kg per person per year) more carbon dioxide than

diet B

Diet A

• releases less carbon dioxide than typical diet

• releases more carbon dioxide than diet B

• releases 1000 (kg per person per year) more carbon dioxide than

diet B

comparisons can be given in terms of correct data or calculations or

proportions for example, typical diet releases 8 times more carbon

dioxide than diet B

For Level 2 both comparison of all three diets and quoting data or

calculation are required.

Total 8

How to answer it

Human Impact on the Atmosphere

What this question tests

This question assesses your understanding of the carbon cycle and how human activities like deforestation and agriculture contribute to global warming. It also tests your ability to interpret data from bar charts and perform comparative calculations.

Part 05.1

Deforestation and CO₂

💡 Key Knowledge

  • Trees remove CO₂ from the atmosphere for photosynthesis.
  • Trees store carbon in their biomass (wood).
  • When trees are cleared, that carbon is released back into the atmosphere.

✅ Correct Answers (Choose one)

  • Reduced/less photosynthesis.
  • Burning of wood/trees.
  • Decay or decomposition of wood by microorganisms.

Examiner Tip: You can also get the mark for mentioning the combustion of fossil fuels in the machinery used to clear the forests.

Part 05.2

Greenhouse Gases

🧠 Exam Technique

The question asks for one other gas. Always read the prompt carefully—it explicitly tells you not to use carbon dioxide.

✅ Correct Answers

  • Methane (the most common answer).
  • Water vapour.
  • Nitrous oxides.
Part 05.3

Meat Production

💡 Key Knowledge

Carbon dioxide is released at almost every stage of the "farm to fork" process.

  • Respiration: Livestock (animals) breathe out CO₂.
  • Transport: Burning fuel in trucks to move meat.
  • Infrastructure: Burning fuel to heat or light farm buildings.

❌ Common Errors

Do not just write "burning." You must specify what is being burnt (e.g., "burning fuel for transport") to get the mark. Avoid mentioning methane here, as the question specifically asks for carbon dioxide.

Part 05.4

Data Analysis: Comparing Diets

Compare the mass of CO₂ released by the three diets.

📐 Step-by-Step Calculations

To get full marks (Level 2), you must use numbers from the graph.

  1. Identify the values:
    Typical Diet = 2000 kg
    Diet A = 1250 kg
    Diet B = 250 kg
  2. Calculate differences:
    Typical vs Diet A: 2000 - 1250 = 750 kg more.
    Typical vs Diet B: 2000 - 250 = 1750 kg more.
  3. Calculate ratios:
    Typical vs Diet B: 2000 / 250 = 8 times more CO₂.

🧠 How to get 4/4 Marks

A "Level 2" response must:

  • Compare all three diets (don't just talk about one).
  • State the general trend (Typical is highest, B is lowest).
  • Include at least one specific calculation or data point from the graph.

✅ Model Answer

"All three diets release CO₂. The typical diet releases the most at 2000 kg per year, while Diet B releases the least at only 250 kg. This means the typical diet releases 1750 kg more CO₂ than Diet B. Diet A is in the middle, releasing 1250 kg, which is 750 kg less than the typical diet."

Topics

Biology · Chemistry · B7: Ecology · C9: Chemistry of the Atmosphere

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.