Concept:Digestion is the breakdown of large, insoluble food molecules into small, soluble forms that can be absorbed into the blood.
Explanation:Food digestion in mammals involves mechanical and chemical processes.
Large food particles are broken into simpler substances like glucose and amino acids.
These simple substances are soluble in water.
Only soluble, small molecules can pass through the intestinal walls into the bloodstream.
Making energy available, growth, and repair are results of using absorbed nutrients, not the direct purpose of digestion itself.
Similarly, digestion does not create or store food materials inside the body.
Therefore, the key role of digestion is to render food substances soluble and absorbable.
Answer:D. render food substances soluble and absorbable