Brad is testing three solutions with litmus paper. after dipping the litmus paper strips in the solutions, he observes two papers turning blue and one turning red. out of the three solutions, how many are acidic?

Out of the three solutions one is acidic because there is a property of acids which states that they turn litmus papers red

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.