Scientists must be able to repeat an experiment and get very similar results; otherwise their conclusions will be questioned. if the results of a repeated experiment are different from the original results, the results of the experiment

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.

Mechanical energy from wind nonrenewable resource