Answer:
A control group is a set standard so that comparisons can be made to see what your experiment did. The experimental group is the group that has been changed. A control group also allows you to determine your variables.
Explanation:
Because nowadays, many horses are domesticated, and food they would have eaten in the wild, they don't usually eat anymore. They have learnt to adapt to eating other foods, like hay, that require molars to ingest. This is why over time, their tooth structure has changed.
Answer:
C. Pepsinogen is the active form of pepsin.
Explanation:
Pepsin is a gastric protease belonging to the aspartic proteinase family which breaks down polypeptide chains into smaller peptides by hydrolyzing peptide bonds. Pepsin is found in the gastric juice where it digests proteins from foods together with other digestive enzymes and hydrochloric acid. Moreover, pepsinogen is a precursor of pepsin which is secreted by the gastric chief cells of the human stomach and then is converted into pepsin (its active form) by hydrochloric acid.
