Answer: The correct statement about digestion is: "Digestion can be both mechanical and chemical, and it occurs both in the mouth and in the stomach."
Step-by-step explanation:
Digestion is a complex process that involves both mechanical and chemical processes to break down food into smaller, absorbable molecules. Mechanical digestion refers to the physical breakdown of food into smaller pieces through actions like chewing, churning in the stomach, and mixing in the intestines. Chemical digestion, on the other hand, involves the breakdown of complex molecules into simpler forms through the action of enzymes and other chemicals.
Mechanical digestion begins in the mouth with chewing and continues in the stomach through the churning and mixing of food with digestive juices. Chemical digestion also starts in the mouth, where saliva contains enzymes (e.g., amylase) that begin the breakdown of carbohydrates. Further chemical digestion occurs in the stomach and continues in the small intestine, where various enzymes break down proteins, fats, and carbohydrates into their component parts for absorption.
Ingestion, on the other hand, refers specifically to the process of taking in food through the mouth. It is the first step of the digestive process but does not encompass the entirety of digestion itself.