Which term describes the first phase of digestion?

Which term describes the first phase of digestion?

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

Answer: (B)

The first phase of digestion is mechanical digestion. In the mouth, teeth chew the food and the tongue helps mix it with saliva, forming a smaller, moistened mass called a bolus. This physical breakdown increases surface area and makes swallowing easier, setting the stage for enzymes to act. While chemical digestion begins with enzymes in saliva and later in the stomach, the initial step described as the first phase is the mechanical one because it is the immediate physical breakdown that starts the digestive process. Peristalsis moves contents along the digestive tract and occurs after this initial breakdown, not as the first phase. Absorption happens after digestion, when nutrients pass through the gut lining.

The first phase of digestion is mechanical digestion. In the mouth, teeth chew the food and the tongue helps mix it with saliva, forming a smaller, moistened mass called a bolus. This physical breakdown increases surface area and makes swallowing easier, setting the stage for enzymes to act. While chemical digestion begins with enzymes in saliva and later in the stomach, the initial step described as the first phase is the mechanical one because it is the immediate physical breakdown that starts the digestive process. Peristalsis moves contents along the digestive tract and occurs after this initial breakdown, not as the first phase. Absorption happens after digestion, when nutrients pass through the gut lining.