Answer: Oxygen from the atmosphere is combined with carbohydrates to liberate the stored energy. Water and carbon dioxide are byproducts. Notice that photosynthesis and respiration are essentially the opposite of one another. Photosynthesis removes CO2 from the atmosphere and replaces it with O2.
Answer: Oxygen is replaced in the atmosphere by the plants as they prepare food (photosynthesis). Carbon dioxide is replaced by the animals for the plants to consume. Plants and Animals are interdependent on each other for survival.
