Answer: Elaboration
Explanation:
From the given case/scenario, we can state that the class finds the second group easier because Dr. Marsh tends to elaborate thing within the second group. Elaboration referred to or known as the act under which one tends to add more data and information to the already existing information in order to create a far much more easier grasp on the subject. It can also be described as adding details or information.
Something that is located beneath the surface of the water is minerals
