Lesson 3.1.1.3

3.1.1.3 The carbon cycle Quiz: AQA Geography, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.1.3, The carbon cycle: 20 multiple choice questions for the AQA Geography (7037), Unit 1: Physical geography, written with Revision Ninja.

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The 20 questions

  1. Which process removes carbon dioxide from the atmosphere and converts it into organic biomass?

    • Decomposition
    • Photosynthesis
    • Respiration
    • Combustion

  2. Which store contains the largest total amount of carbon on Earth?

    • Atmosphere
    • Biosphere
    • Lithosphere
    • Hydrosphere

  3. Which process releases carbon dioxide when microorganisms break down dead organic material?

    • Decomposition
    • Weathering
    • Photosynthesis
    • Sequestration

  4. Which process transfers carbon long-term from the ocean into the lithosphere?

    • Evaporation
    • Sedimentation
    • Respiration
    • Outgassing

  5. Which chemical equation represents the process of photosynthesis?

    • 6CO2 + 6H2O -> C6H12O6 + 6O2
    • 6CO2 + 6O2 -> C6H12O6 + 6H2O
    • C6H12O6 + 6O2 -> 6CO2 + 6H2O
    • 6H2O + 6O2 -> C6H12O6 + 6CO2

  6. Which biological process releases carbon dioxide from living organisms into the atmosphere?

    • Respiration
    • Decomposition
    • Photosynthesis
    • Combustion

  7. Which geological process transfers carbon from the lithosphere into the atmosphere?

    • Carbon sequestration
    • Volcanic outgassing
    • Chemical weathering
    • Sedimentation

  8. If 440 Mt of CO2 is emitted, how much pure carbon is released?

    • 120 Mt
    • 440 Mt
    • 320 Mt
    • 160 Mt

  9. A forest stores 150 tonnes of carbon per hectare. If deforestation removes 20%, how much carbon is lost?

    • 120 tonnes
    • 50 tonnes
    • 30 tonnes
    • 20 tonnes

  10. Fossil emissions equal 9 Gt C, ocean uptake 2.5 Gt C, and atmospheric gain 4 Gt C. Calculate the land sink.

    • 3.0 Gt C
    • 2.5 Gt C
    • 6.5 Gt C
    • 1.5 Gt C

  11. Which human action releases stored biomass carbon into the atmosphere most rapidly?

    • Afforestation
    • Peatland restoration
    • Soil compaction
    • Forest burning

  12. Which environmental change causes the release of stored carbon from permafrost regions?

    • Increased snowfall
    • Global warming
    • Afforestation
    • Glacial advance

  13. Which biological process acts as a carbon sink at plant scale?

    • Decomposition
    • Photosynthesis
    • Transpiration
    • Respiration

  14. Which time scale best describes carbon transfers caused by chemical weathering of rocks?

    • Millennia
    • Seasonal
    • Annual
    • Decadal

  15. What does a carbon budget calculate to balance inputs and outputs?

    • Lithosphere and atmosphere
    • Biomass and soils
    • Sources and sinks
    • Oceans and vegetation

  16. Warmer oceans absorb less carbon dioxide, increasing atmospheric warming. What type of feedback loop is this?

    • Neutral feedback
    • Negative feedback
    • Radiative equilibrium
    • Positive feedback

  17. Why is biomass energy often classified as carbon neutral over a full forestry rotation?

    • Regrowth absorbs carbon
    • Wood never burns
    • Trees emit oxygen
    • Ash stores carbon

  18. Which store holds carbon for millions of years in the long-term carbon cycle?

    • Terrestrial biosphere
    • Surface ocean
    • Sedimentary rock
    • Atmosphere

  19. What does land clearance initially turn a terrestrial ecosystem into?

    • Carbon neutral zone
    • Net carbon source
    • Permanent store
    • Net carbon sink

  20. What transfers carbon from the ocean surface to deep ocean sediments via biological activity?

    • Thermal expansion
    • Ocean acidification
    • Thermohaline circulation
    • Biological pump

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