Final answer:
Chemosynthesis is a process that uses chemical energy to produce food, while photosynthesis converts water, carbon dioxide, and light energy into glucose and oxygen. Photosynthesis is essential for life on Earth as it provides energy for all living things.
Step-by-step explanation:
Chemosynthesis is a process in which some organisms, like bacteria, use chemical energy to produce food. It doesn't require light, instead, it uses inorganic molecules like hydrogen sulfide or ammonia. In contrast, photosynthesis is a process used by plants and some bacteria to convert carbon dioxide, water, and light energy into glucose and oxygen. Photosynthesis is vital for the existence of life on Earth, as it provides over 99% of the energy for all living things. Both processes involve the creation of organic molecules, but they differ in the source of energy they use.