Final answer:
A. Catabolic reactions are the chemical reactions that release energy by breaking down larger molecules into smaller units, like in the breakdown of glucose during cellular respiration.
Step-by-step explanation:
Those chemical reactions taking place in the body and accompanied by a release of energy are known as catabolic reactions. Catabolic reactions involve the breakdown of molecules into smaller units, which results in the release of energy. An example of a catabolic reaction is the breakdown of glucose during cellular respiration, a process where energy is released that cells utilize for various life processes.
When comparing options such as anabolic reactions, which are endergonic as they consume energy to build up larger molecules from smaller ones, or exergonic reactions, which release energy, it is the catabolic reactions that are exergonic and pertinent to the digestion of food and the release of energy. These reactions are a part of metabolic processes that maintain life by providing energy for the body's needs.
Metabolic processes, which include both catabolic and anabolic reactions, are constantly occurring in the body, making up what is known as metabolism. Metabolism is key to maintaining life, balancing the breakdown of substances for energy and the synthesis of new compounds needed by the organism.