A is a particle with no charge

What are the choices?

Neutrons = a neutral charge (0)
protons = positive charge
electrons = negative charge

hope this helps!

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.