Ecology is the study of how: a. humans affect the environment. b. atoms make up the environment. c. evolution affects nature. d. organisms interact with each other and their nonliving environment. e. energy runs the environment.

Organisms interact with each other and their non living environment

The zone your looking for is the intertidal zone.

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.