Answer:
the answer is D
Explanation:
Cellular respiration is the process by which living cells break down glucose molecules and release energy. The process is similar to burning, although it doesn’t produce light or intense heat as a campfire does. This is because cellular respiration releases the energy in glucose slowly, in many small steps. It uses the energy that is released to form molecules of ATP, the energy-carrying molecules that cells use to power biochemical processes. Cellular respiration involves many chemical reactions, but they can all be summed up with this chemical equation:
\[\ce{C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy} \nonumber\]
where the energy that is released is in chemical energy in ATP (vs. thermal energy as heat). The equation above shows that glucose (\(\ce{C6H12O6}\)) and oxygen (\(\ce{O_2}\)) react to form carbon dioxide (\(\ce{CO_2}\)) and water \(\ce{H_2O}\), releasing energy in the process. Because oxygen is required for cellular respiration, it is an aerobic process.
Cellular respiration occurs in the cells of all living things, both autotrophs and heterotrophs. All of them burn glucose to form ATP. The reactions of cellular respiration can be grouped into three stages: glycolysis, the Krebs cycle (also called the citric acid cycle), and electron transport. Figure \(\PageIndex{3}\) gives an overview of these three stages, which are also described in detail below.
