Following passage is about the vitamin C which is synthesized in plants and in the livers of most vertebrates. Read the passage and answer the questions at the end of it.
Humans, monkey, and guinea pigs do not have the enzymes necessary for the biosynthesis of vitamin C, so

they must include the vitamin in their diets. It is also required for the synthesis of collagen, which is the structural protein of skin tendons, connective tissue and bone.