DP Biology (first assessment 2025)

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Question 23M.2.SL.TZ1.7b

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Date May 2023 Marks available [Maximum mark: 5] Reference code 23M.2.SL.TZ1.7b
Level SL Paper 2 Time zone TZ1
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 5]
23M.2.SL.TZ1.7b
(b)

Outline the stages of the carbon cycle that involve plants or materials made by plants.

[5]

Markscheme
  1. absorption/diffusion of carbon dioxide from the atmosphere/water by plants;
  2. photosynthesis fixes/converts carbon (dioxide) to carbohydrates/carbon compounds;
  3. respiration in plants converts carbohydrates/carbon compounds to carbon dioxide;
  4. saprotrophs/detritivores digest dead plants/plant matter releasing carbon/carbon dioxide;
    OR
    decomposition returns carbon to the soil/releases CO2 to atmosphere/water/environment
  5. peat forms when decomposition of dead plant matter is incomplete storing carbon/ creating a reservoir;
    OR
    fossilization of carbon stores carbon as coal/oil/natural gas;
  6. forest fires/combustion of plants converts (carbohydrates/carbon compounds) to carbon dioxide;
  7. plants are eaten by consumers (moving carbon in the food chain)
  8. humans use plant products for making cloth/household items/building/arts creating a reservoir for carbon
    OR
    Humans burn fossil fuels releasing CO2;
  9. Plants act as carbon sinks/reservoirs

 

Carbon may be used in place CO2 an carbohydrates

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