Metabolism is
a. a measure of the hydrogen ion concentration in a solution
b. the energy required to start a chemical reaction
c. all of the chemical reactions in an organism required to sustain life
d. a chemical reaction in which the substrates trade constituent parts

answer; /// i believe that the correct answer is; ///a combination of the birth and death

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.