The answer would be ecosystem.
- I hope this helps! (:
Pepsin is an Enzyme that is found in the stomach to break down protein.The Pepsin breaks the protein down into smaller peptides at low pH vale.
There is also one within the small intestine called Chymotrypsin and also the Carboxypeptidase.
Hope this helps and if you are still unsure read up on these to help you.
Gene pool is the variety and available genes in a specific population of a species .