Which is the first of the five steps of the digestive process?

• A. Chemical
• B. Absorption
• C. Mechanical
• D. Peristalsis

Answer: (C)

Mechanical digestion happens first because it is the initial physical breakdown of food, starting right in the mouth with chewing and mixing, and continuing with stomach grinding. This physical action reduces particle size and increases surface area so enzymes can work more effectively later. Once the food has been physically broken down, chemical digestion begins as enzymes and stomach acids start to chemically break down nutrients. Propulsion by peristalsis moves the digested material along the gut, and absorption occurs later as nutrients pass into the bloodstream. In animals, the exact mechanics can vary, but the sequence—physical breakdown first, then chemical digestion, then movement, then absorption—starts with mechanical digestion.