Answer:
d < -60
Step-by-step explanation:
Let d represent the depth of the researchers' second dive.
Given;
Depth of First dive = -60 ft
It was stated that in their second dive, the researchers explore a deeper depth, That is depth deeper than 60 ft.
Since the depth of 60ft is represented by the integer -60,
Deeper depth would be represented by integers less than -60.
So, d can be represented as;
d < -60