Explain why the carbon cycle and the oxygen cycle are closely related?

The oxygen cycle is closely linked to the carbon cycle and the water cycle (see hydrological cycle). ... Carbon dioxide enters the carbon cycle or is taken up by plants for photosynthesis. During photosynthesis oxygen is evolved by the chemical splitting of water and returned to the atmosphere

Explanation:

The oxygen cycle is closely linked to the carbon cycle and the water cycle (see hydrological cycle). In the process of respiration oxygen is taken in by living organisms and released into the atmosphere, combined with carbon, in the form of carbon dioxide。  

Explanation:

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

the answer will be a) proteins i believe