Natural Science CLEP Prep Practice Exam

Photosynthesis is a process that allows plants to convert light energy into chemical energy, which is then used to create food. Sunlight is the primary source of energy for photosynthesis as without light, the plant would not be able to carry out this process. Water (A) and carbon dioxide (B) are also necessary components for photosynthesis, but they serve as reactants, not sources of energy. Oxygen (D) is also a product of photosynthesis, but it is not the primary source of energy. Without sunlight, photosynthesis would not be able to occur and plants would not be able to produce the necessary food for their survival. Therefore, C is the correct option as it directly states the primary source of energy for photosynthesis.