Final answer:
ATP is necessary for life because it provides energy to cells and is involved in various processes such as building large molecules, muscle contraction, electrical signal transmission, and as the body's fuel source.
Step-by-step explanation:
ATP is necessary for life because it provides energy to cells. ATP functions as the energy currency of the cell and can be used to fill any energy need of the cell. It is involved in various processes such as building large molecules, muscle contraction, electrical signal transmission, and as the body's fuel source.