Explain how two different human activities increase the levels of greenhouse gases in the atmosphere. In your answer, name the greenhouse gas produced by each activity.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Driving cars and other vehicles burns fossil fuels, releasing carbon dioxide (CO₂) into the atmosphere.
The use of livestock farming, especially cattle, produces methane (CH₄) through enteric fermentation and manure management.
The use of livestock farming, especially cattle, produces methane (CH₄) through enteric fermentation and manure management.
Examiner tips
- Use the command word ‘explain’ – give a brief description of each activity and the gas it releases. Use the exact terms CO₂ and CH₄ as they are the expected answers. Show the two activities are distinct (e.g. transport vs livestock).
Common mistakes
- Confusing CO₂ with CH₄ for the same activity. Naming a gas that is not a greenhouse gas (e.g. N₂O for a non‑greenhouse activity). Using vague phrases like ‘burning things’ without specifying the activity.
Mark scheme (4 marks)
- Names a valid human activity that produces a greenhouse gas (e.g. driving/burning fossil fuels for electricity/raising livestock/decay of organic waste in landfill sites)
- Correctly names the greenhouse gas linked to that first activity (CO₂ for driving/electricity; methane/CH₄ for livestock/landfill)
- Names a second valid human activity that produces a different greenhouse gas (must be a distinct activity from the first)
- Correctly names the greenhouse gas linked to that second activity, and this must be a different gas from the one given for the first activity
Key terms in this question
greenhouse gases · human activities · atmosphere
Related
- All AQA GCSE Chemistry (8462) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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