Answer:
A
Explanation:
Oxygen is formed from carbon dioxide in ____(1)____, while carbon dioxide is formed from oxygen in ____(2)____.
A (1) photosynthesis, (2) cellular respiration
B(1) cellular respiration, (2) photosynthesis
C (1) fermentation, (2) anaerobic respiration
D(1) aerobic respiration, (2) photosynthesis