The correct answer is:

A is false but R is true.

Assertion (A): All the proteins in our food are digested in the small intestine only.

This statement is false. While a significant amount of protein digestion occurs in the small intestine, it is not the only site of protein digestion. Protein digestion begins in the stomach, where the enzyme pepsin breaks down proteins into smaller peptide chains.

Reason (R): The protein-digesting enzymes from the pancreas are released into the small intestine.

This statement is true. The pancreas secretes several protein-digesting enzymes, including trypsin, chymotrypsin, and carboxypeptidase, into the small intestine. These enzymes further break down the peptide chains into smaller peptides and individual amino acids, which can then be absorbed into the bloodstream.

Therefore, the correct answer is:

A is false but R is true. Protein digestion begins in the stomach with pepsin, and the protein-digesting enzymes from the pancreas are released into the small intestine for further digestion.