Which of the following is false regarding the protein pepsin? A. Pepsin hydrolyzes peptide bonds.
B. Pepsin is a type of protease.
C. Pepsinogen is the active form of pepsin.
D. Pepsinogen self-cleaves at the pH found in the stomach.
E. None of the above are false.

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.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation: