Final answer:
Photosynthesis is a complex process in which certain living things use sunlight to manufacture energy-storing products while releasing oxygen. Light is essential for photosynthesis as it provides the energy needed for ATP synthesis and the reduction of NADP+ to NADPH.
Step-by-step explanation:
Photosynthesis is a complex sequence of chemical reactions that allows certain living things to use sunlight to manufacture products that store energy, such as carbohydrates, while releasing oxygen as a by-product. The process of photosynthesis requires light to provide the energy needed for the synthesis of ATP and the reduction of NADP+ to NADPH. Light is essential for photosynthesis because it is used to trap light energy and convert it into chemical energy in the form of ATP and NADPH. Without light, photosynthesis cannot occur.