SAT Biology Subject Test Practice Questions

Answer: D, I and II only. In photosynthesis, water and carbon dioxide are used to create organic compounds using sunlight as energy.

Key Takeaway: Photosynthesis is the process by which plants create their own nutrients. Oxygen is not needed in this process, but is released as a byproduct of it in the same manner as carbon dioxide is released as a byproduct of aerobic respiration in humans. These combined processes serve to benefit both groups, as oxygen and carbon dioxide are constantly recycled into the environment.