Which of the peas' traits,
Yellow or Green, is
recessive? Explain your
answer.

Mendel's gene involved in pea color decides whether the chlorophyll in the pea will be broken down or degraded. When this gene isn't working, the chlorophyll stays around and the pea is green. So in this case the recessive trait is indeed due to a broken gene.

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.

They are both used to view parts of the cell