How does our ribs and diaphragm enable breathing in and out to occur?

When we breath in muscles move our ribs move up and out and our diaphragm contracts. This increases the volume in our chest cavity and decreases the pressure. This means air is pulled in and our lungs fill. When we breath out the diaphragm relaxes and our ribs move inwards. This decreases the volume of our chest cavity and increases the pressure, forcing the air out of our lungs.

The correct answer is c

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.