Answer: To grow and reproduce, all creatures require energy. Cellular respiration is utilized by many organisms (including all plants) to create ATP, which is needed for cellular energy. As a substrate, carbohydrates such as glucose are used in the respiration reaction. Plants produce their own fuel for respiration through photosynthesis, but humans consume food to do so. Plants would not be able to breathe if photosynthesis did not occur. Furthermore, carbohydrates created during photosynthesis are needed to construct plant cell components such as the cellulose cell wall.
Explanation: Facts... I took this last year in 9th or 10th grade.