☝︎sorry I didn’t find science. ANYWAYS-

1. Could the extinction of lions affect the grass population? Why or why not. EXPLAIN PLS（╹◡╹）♡ in a sentence to be specific ^^

Yes. Lions are predators to grass eating species, so without the limitation of said species, there would be less chance for grass to grow as it is eaten more because the prey species are not killed off.

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.