Which of the following does not describe bacteria?

a) they produce most of the earth's oxygen and clean the air of pollution. b) they break down food in the human intestines. c) they break down harmful products. d) they break down dead organic material so it can be recycled into a usable form for other organisms.

"A" does not describe bacteria. Bacteria use cellular respiration to produce energy, and therefore do not produce oxygen. However, millions of years ago, cyanobacteria did produce oxygen.

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.

The answer is letter c