Answer:
<em>The long-term carbon cycle is the main controller of the concentration of atmospheric carbon dioxide and (along with the sulphur cycle) atmospheric oxygen over a geological timescale1,2. It can be represented succinctly by the generalized reactions3,4: Figure 1: A model of the long-term carbon cycle</em>
<em><u>A</u></em><em><u>.</u></em><em>When the animals die, they decompose, and their remains become sediment, trapping the stored carbon in layers that eventually turn into rock or minerals. Some of this sediment might form fossil fuels, such as coal, oil, or natural gas, which release carbon back into the atmosphere when the fuel is burned.</em>
<em><u>B</u></em><em><u>.</u></em><em><u>Cells use oxygen to "burn" food for energy. Water and carbon dioxide are produced as wastes. The cells in both plants and animals perform respiration. Carbon dioxide is also released into the atmosphere when fuels are burned, such as in automobiles or factories</u></em>
<em><u>Cells use oxygen to "burn" food for energy. Water and carbon dioxide are produced as wastes. The cells in both plants and animals perform respiration. Carbon dioxide is also released into the atmosphere when fuels are burned, such as in automobiles or factories </u></em>
<em><u>c</u></em><em><u>.</u></em><em><u>During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose</u></em>
<em><u>d</u></em><em><u>.</u></em><em><u>Fossil fuels are made from decomposing plants and animals. These fuels are found in the Earth's crust and contain carbon and hydrogen, which can be burned for energy. Coal, oil, and natural gas are examples of fossil fuels.</u></em>
