Final answer:
Digestion is the enzymatic process of breaking down food into smaller molecules, which includes both mechanical and chemical digestion. Absorption is the uptake of these small molecules into the bloodstream, which occurs mainly in the small intestine.
Step-by-step explanation:
Digestion Process
The process of breaking down large molecules of food into smaller substances through the action of enzymes is called digestion. This process can be broken down into two key types: mechanical digestion and chemical digestion. Mechanical digestion starts in the mouth with the physical process of chewing and continues in the stomach where the food is mixed with digestive juices. Chemical digestion also begins in the mouth with saliva breaking down the food and continues in the stomach, where stomach enzymes further digest the food into small nutrient molecules suitable for absorption.
Absorption and Assimilation
Following digestion, absorption occurs, primarily in the small intestine, where the small nutrient molecules enter the bloodstream. These molecules travel throughout the body to be used by cells. Assimilation is the process where these nutrients are then taken up by the cells and utilized for various functions, such as energy production, growth, and repair. Meanwhile, excretion is the process of removing waste material from the body that cannot be digested or absorbed.