All the following enzymes are secreted by gastrointestinal system EXCEPT

Correct option is D

The gastrointestinal system secretes several digestive enzymes, but angiotensin is a hormone, not an enzyme, and is primarily involved in blood pressure regulation via the renin-angiotensin system, not digestion. Explanation of each option: • (a) Ptyalin – Also known as salivary amylase, secreted in the mouth to break down starch. • (b) Pepsin – A gastric enzyme secreted in the stomach; it digests proteins into peptides. • (c) Chymotrypsin – A pancreatic enzyme released into the small intestine, it also helps digest proteins. • (d) Angiotensin – Correct. A peptide hormone formed in the blood, it is not secreted by the GI system and plays no role in digestion.