Final answer:
The digestion of protein into amino acids is the most likely to be an exergonic reaction as it releases energy through the breakdown of complex molecules into simpler ones.
Step-by-step explanation:
An exergonic reaction is a chemical reaction where energy is released to the surroundings. The breakdown of molecules in catabolic reactions, such as the digestion of protein into amino acids, is an example of an exergonic process because it releases energy that cells can use for work. In contrast, anabolic reactions, such as the formation of cellulose from glucose molecules, DNA replication, or the synthesis of a phospholipid from glycerol and fatty acids, require energy input and are considered endergonic reactions.
Based on this understanding, the reaction most likely to be exergonic is D. the digestion of protein from food into amino acids. This catabolic reaction leads to the breakdown of larger protein molecules into smaller units, releasing energy in the process that the body can use for various cellular functions.