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Volume 30, Number 4, April 2017
Answers and instructions
Carbon cycle quiz
This quiz (available to download separately from this issue’s GeographyReviewExtras) is designed for
classroom use. It could be used:

as a ‘starter’ activity to see what students already know about the carbon cycle or as a quiz at
the end of the topic

as a ‘team quiz’ just for fun, but to try and reinforce some key terminology and concepts
The quiz is marked out of 10.The answers are provided below along with some additional information
designed to promote further discussion in the classroom.
Answers
1
The correct answer is C, 400 ppm (parts per million). This represents a 48% increase over
natural levels. The highest level recorded in the 800,000 year long ice-core record is about 300 ppm.
2
The correct answer is B, a transfer of carbon between carbon pools/stores. The largest annual
flux is between the atmosphere and vegetation/soil, and the second largest between the oceans and
the atmosphere.
3
The correct answer is B, fossil fuels. These are simply the buried, fossilised and altered
remains of phytoplankton and zooplankton (oil and gas) and terrestrial plants (coal and peat).
4
The correct answer is D, geological. This carbon store dwarfs the others in terms of volume.
The deep oceans, soil and fossil-fuel reserves are also very large stores.
5
The correct answer is D, methane. Its chemical formula is CH4, whereas the other gases
contain no carbon (SO2, NO/NO2 H2O).
6
The correct answer is C, basalt. This rock, being igneous, contains no carbon. The other rocks
all do, so are part of the geological carbon pool. Limestone consists of calcite/aragonite which is
calcium carbonate (CaCO3). This is also the case with chalk which is the calcium carbonate remains of
planktonic coccoliths. Shale often contains large volumes of trapped hydrocarbons and carbonaceous
fossils. Metamorphic marble is also a carbon store, being formed from metamorphosis of limestone.
7
The correct answer is A, phytoplankton. The biological pump is part of the marine carbon
cycle. Phytoplankton in the oceans sequester carbon to make their tiny shells (or ‘tests’) which than
become part of ocean-floor sediments, and eventually rocks within the rock cycle processes.
8
The correct answer is D, methane. Methane makes up 15–16% of greenhouse gas emissions,
coming from landfill, paddy fields, cattle farming, gas pipeline leaks and permafrost. It is a much more
powerful greenhouse gas than carbon dioxide in terms of its global warming potential (GWP) see:
https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
9
The correct answer is C, soil.
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10
The correct answer is C, 10 GtC per year.
This resource is part of GEOGRAPHY REVIEW, a magazine written for A–level students by subject experts.
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Hodder & Stoughton © 2016
www.hoddereducation.co.uk/geographyreview