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| 5813895324 | (a) The atmosphere is one important carbon reservoir. (i) Describe a biological process by which carbon is removed from the atmosphere and converted to organic molecules. | Photosynthesis: the process by which plants/autotrophs take in carbon dioxide from the atmosphere and convert it into food/glucose/sugar/complex carbohydrates; plants/autotrophs fix carbon into food/glucose/sugar/complex carbohydrates. | 0 | |
| 5813898995 | (ii) Describe a biological process by which carbon is converted from organic molecules to a gas and returned to the atmosphere. | Respiration breaks down food/glucose/sugar/complex carbohydrates and releases CO2 into the atmosphere | 1 | |
| 5813899759 | (b) Oceans and terrestrial systems are also important carbon reservoirs. (i) Explain how atmospheric carbon is incorporated into two oceanic sinks. | Carbon (CO2) can be taken up by organisms like phytoplankton for photosynthesis • Carbon can be taken up by marine organisms and used for shells, skeletons, coral, etc | 2 | |
| 5813900900 | (ii) Identify one terrestrial sink, other than fossil fuels, that stores carbon for thousands to millions of years. | • Limestone or sedimentary rocks | 3 | |
| 5813902343 | (c) The burning of fossil fuels has been shown to increase the concentration of carbon in the atmosphere. Discuss TWO other human activities that increase the concentration of carbon in the atmosphere. | Biomass burning releases carbon (CO, CO2, carbon particulates) Deep plowing or strip mining disrupts soil and releases carbon (CO2) | 4 | |
| 5813903612 | (d) Identify an environmental problem that results from elevated atmospheric carbon concentrations. Discuss one consequence of the problem you identified. | Environmental problem: Ocean acidification Environmental Consequence: " shells of marine organisms may dissolve • lower pH may be below the tolerance level of some species | 5 | |
| 5813904754 | (e) Phosphorus is another element important to all organisms. (i) Describe one major way in which the phosphorus cycle differs from the carbon cycle. | Phosphorus cycle does not typically have a gas/atmospheric phase | 6 | |
| 5813905827 | (ii) Identify one reason that phosphorus is necessary for organisms. | It is necessary for the formation of DNA and RNA | 7 |
