James wants to create a self-sustaining ecosystem, or vivarium. which method would most likely result in an ecosystem that is viable for the longest amount of time with no additional care?

True to the fact it is actually false

All of them are man made

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.