Answer:
While photosynthesis requires carbon dioxide and releases oxygen, cellular respiration requires oxygen and releases carbon dioxide. ... Without oxygen, much less ATP would be produced. Cellular respiration and photosynthesis are important parts of the carbon cycle.Without photosynthesis, there would be no sugar, without which there could be no cellular respiration. ... Both animal cells and plant cells depend on cellular respiration for their energy needs, because both animal cells and plant cells need ATP.