Which physiological process follows ingestion?

The physiological process that immediately follows ingestion is digestion. After food is taken into the body, the digestive system begins to break it down into smaller, absorbable components. This process involves both mechanical and chemical breakdown, where the physical act of chewing and the enzymatic action of saliva, stomach acids, and digestive enzymes transform the food into a form that can be assimilated by the body.

To clarify the context of the other options: absorption occurs after digestion, as the nutrients from digested food are taken up by the cells in the intestines. Egestion refers to the expulsion of undigested waste from the body, which occurs after digestion and absorption. Respiration is a separate metabolic process focused on gas exchange and energy release from nutrients, not directly related to the initial processing of ingested food. Thus, digestion is indeed the correct answer to the question of what physiological process immediately follows ingestion.