His immune system is using the first line of defense. His body is using purging methods that is caused by irritation of the hairs in his nose. This defense system<span> uses physical and chemical barriers that are prepared to defend the body from infection.</span>
Either mechanical or physical. I would say physical though.
This is very true all of the above
Their chemical breakdown begins in the stomach<span> and continues in the large intestine. Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the </span>pancreas<span> and cleave proteins into smaller peptides. Carboxypeptidase, which is a pancreatic brush border enzyme, splits one amino acid at a time.</span>