Lesson 5.7.1

5.7.1 Controversial conclusions, carbon cycle and sustainable resources Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.7.1, Controversial conclusions, carbon cycle and sustainable resources: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 5: On the Wild Side, written with Revision Ninja.

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The 20 questions

  1. Which process removes carbon dioxide from the atmosphere?

    • Photosynthesis, in which plants fix carbon dioxide into carbohydrates
    • Combustion of fossil fuels, which releases carbon dioxide into the air quickly
    • Decomposition of dead organic matter by microbes, which releases carbon dioxide
    • Aerobic respiration in animals, which releases carbon dioxide as a waste product

  2. Which process returns carbon dioxide to the atmosphere from living organisms?

    • Carbon capture by soil minerals, which permanently locks carbon into rock layers
    • Reforestation, in which new trees take up carbon dioxide from the air as they grow
    • Aerobic respiration, in which glucose is oxidised and carbon dioxide is released as a waste product
    • Photosynthesis, in which carbon dioxide is taken in and fixed by chloroplasts into glucose

  3. Reforestation is considered a useful way to manage carbon because:

    • Trees release large amounts of methane, which is then broken down into carbon dioxide
    • Trees stop all decomposition in the soil beneath them, so no carbon is released
    • Growing trees take up carbon dioxide and store carbon in their biomass and soil
    • Trees emit oxygen only at night, which lowers the concentration of carbon in the air

  4. Biofuels are often described as more sustainable than fossil fuels mainly because:

    • They produce no carbon dioxide at any stage of growing, harvesting or processing
    • They are formed from ancient carbon that has been locked in rocks for millions of years
    • The carbon released on burning was recently taken from the atmosphere by the crop as it grew
    • They release less energy per gram, which means less carbon is produced in combustion

  5. A key criticism of biofuels is that they:

    • Cannot be burned in any engine, so they are only used in laboratory experiments
    • Produce more carbon dioxide per unit of energy than petrol or diesel in every case
    • Remove all soil nutrients permanently, so no other crop can be grown on the same field
    • Compete with food crops for agricultural land

  6. Why must scientists extrapolate data when predicting future climate change?

    • Because extrapolation removes all uncertainty from the measured temperature records
    • Because predictions require values beyond the range of the measured data
    • Because models only work with data that was recorded at exactly the same time each year
    • Because data can only be used if it is taken from a single location on Earth

  7. Which is a limitation of climate models?

    • They can only describe the climate of the past and cannot be used to make any predictions
    • They are identical for every region of the world and cannot show local differences
    • They rely on assumptions and simplifications
    • They ignore carbon dioxide completely, so they can only predict changes in temperature from the sun

  8. Why can scientific conclusions about controversial issues such as climate action sometimes depend on who reaches them?

    • Because scientific evidence changes its meaning depending on the colour of the laboratory
    • Because the interpretation of evidence can be influenced by the values, funding or interests of those who draw conclusions
    • Because all data about climate are kept secret and so no conclusions can ever be checked
    • Because only one scientist is allowed to publish conclusions about climate change

  9. The peer review process mainly helps to:

    • Check the validity of new evidence and conclusions before they are accepted by the scientific community
    • Guarantee that every conclusion in a journal is correct for ever after publication
    • Remove all disagreement between scientists so that a single theory is accepted
    • Provide funding for research teams who want to test controversial claims

  10. A carbon cycle diagram shows 100 units of carbon dioxide taken in by photosynthesis per year and 85 units released by respiration and decomposition. What is the net change in atmospheric carbon from this part of the cycle?

    • Addition of 185 units per year to the atmosphere from these processes alone
    • Removal of 15 units per year from the atmosphere by these processes alone
    • Addition of 15 units per year to the atmosphere from these processes alone
    • No change at all, because photosynthesis and respiration always balance exactly

  11. Which best describes the relationship between biofuel use and the carbon cycle?

    • Biofuels return carbon that plants recently fixed, but their full impact depends on land use and processing emissions
    • Biofuels do not interact with the carbon cycle, because carbon in fuel is separate from carbon in plants
    • Biofuels add carbon that was stored for millions of years, so they always increase the amount of carbon in the air
    • Biofuels remove all carbon from the cycle permanently, so no carbon returns to the atmosphere

  12. Sustainable management of a forest for timber and conservation is an example of managing:

    • The conflict between human needs and conservation, by balancing resource use against ecosystem protection
    • A problem in which carbon is removed from the atmosphere by replacing forests with cities
    • A case in which one species is protected at the expense of every other living organism
    • A conflict in which humans try to remove all species from an area to make it safer

  13. Which is an example of an effective management strategy for the conflict between human needs and conservation?

    • Reforestation combined with the use of sustainable resources such as sustainably managed biofuels
    • Draining wetlands to create farmland, with no replanting or monitoring of the affected species
    • Replacing native forest with a single fast-growing species that is harvested every year
    • Burning all unused forest in order to release stored carbon before it can be lost

  14. The carbon dioxide released from burning a biofuel crop is generally considered:

    • Far greater than the carbon dioxide released by fossil fuels in every possible case
    • Impossible to measure, so no assessment of its carbon impact can ever be made
    • Entirely absorbed by the ocean, so the atmosphere is never affected by the combustion
    • Roughly balanced by the carbon dioxide taken up during growth, if the crop is replanted and managed

  15. Which process in the carbon cycle is carried out mainly by decomposers?

    • Fixing carbon dioxide into glucose in the chloroplasts of leaves
    • Absorbing carbon dioxide directly through the surface of the ocean
    • Storing carbon permanently as coal in deep geological layers
    • Breaking down dead organic matter and returning carbon dioxide to the atmosphere

  16. Which statement is most accurate about climate projections?

    • Projections are accepted without question once they appear in a national newspaper
    • Projections are certain because they are produced by computer models built from measured data
    • Projections are useful for informing decisions, but they should be treated with awareness of their assumptions and uncertainty
    • Projections are useless because the future cannot be predicted by any scientific method

  17. A community replants a degraded hillside with native trees. Which combined benefit best explains why this is considered effective management?

    • It ensures that only one species can survive on the hillside, which simplifies management
    • It increases the speed at which carbon dioxide is released from the soil into the air
    • It increases carbon storage and supports biodiversity while still meeting local needs for timber and land use
    • It removes all human use from the land, which means no benefit to the community is possible

  18. Which statement best evaluates the view that a single scientific conclusion on climate action is always objective?

    • This is an oversimplification, since the evidence may be incomplete and the interpretation can depend on values and interests
    • This is correct, because every scientist agrees on every detail of climate action at all times
    • This is incorrect, because scientific conclusions are never based on any evidence at all
    • This is correct, because scientific conclusions are always produced by machines that cannot be biased

  19. Which carbon cycle process would most increase atmospheric carbon dioxide over a short period?

    • Formation of limestone in ocean sediments, which locks carbon into rock over long periods
    • Reforestation of previously cleared land, which stores carbon in new tree biomass
    • Photosynthesis by a growing forest, which removes carbon dioxide from the atmosphere
    • Large-scale combustion of fossil fuels

  20. Atmospheric carbon dioxide is rising mainly because:

    • Carbon released by burning fossil fuels exceeds the amount taken up by natural carbon sinks
    • Volcanoes have released more carbon dioxide than all human activity combined since 1900
    • Animals are exhaling more carbon dioxide because the atmosphere now contains more oxygen
    • Plants have stopped carrying out photosynthesis in most regions of the world since the 1950s

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