Answer:
D.Sharks are streamlined for active swimming at mid-depths, while skates move about mostly on the ocean bed.
Step-by-step explanation:
Sharks are known to be active off the bottom of oceans and in mid depth which has a high salinity and the streamlined body helps it to move in this kind of saline conditions.
The Skates however don’t move much and are always at the ocean bed.
This is why Sharks are streamlined for active swimming off the bottom, while skates have flat bodies move about mostly on the ocean bed is the right choice.