Photosynthesis is used by plants to crest food. This is essential to all life because of the oxygen plants give off in the process, and the food source the plant becomes.
Combustion is the burning of a substance. It could be complete or could be incomplete. It changes the form of carbon and so it plays it's role in cycle
High concentration and passive transport
Answer:
neither
Explanation:
because humans are the ones that make energy available for cell activity
