The process of food digestion in mammals would

Analyze the question: It asks about the purpose or main result of digestion in mammals.

Explain the concept: Digestion is the breakdown of large, complex, insoluble food molecules into small, simple, soluble molecules. These can pass through the walls of the small intestine (ileum) into the blood. Examples:

• Starch → glucose (by amylase)
• Proteins → amino acids (by proteases)
• Fats → fatty acids and glycerol (by lipase)

Evaluate each option:

• A. Make energy immediately available to the body: Incorrect. Energy is released by respiration, which comes after digestion, absorption and transport.
• B. Promote growth and repair of tissues: Incorrect. This is the function of proteins after assimilation, not of digestion itself.
• C. Provide sufficient food materials within the body: Incorrect. Digestion does not add food. It only changes food already eaten.
• D. Render food substances soluble and absorbable: Correct. This is exactly what digestion does. It converts insoluble, large molecules into soluble, small ones that can be absorbed into the bloodstream.

Answer: D

Tip: Remember the sequence Ingestion → Digestion → Absorption → Assimilation. Digestion is about preparing food for absorption. Energy release, growth and repair come later, at the assimilation and respiration stages.