Which process of genetic recombination involves genes from both parents

Meiosis is a process of genetic recombination. It is a cell division process in which a single cell divides twice to produce four cells containing half the original amount of genetic information. This provides recombination of genes from both parents.

What's the yellow wallpaper?

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.