Metabolism is the correct answer because it refers to the collective term for the eight life processes, which include nutrition, respiration, excretion, transportation, regulation, synthesis, growth, and reproduction. These processes are essential for the maintenance and functioning of living organisms. Metabolism involves the conversion of food into energy, the elimination of waste products, the transportation of nutrients and gases, the regulation of internal conditions, the synthesis of complex molecules, and the growth and reproduction of cells. Therefore, metabolism encompasses all the vital processes necessary for life.