Why Do Skates and Rays Have Flattened Bodies, While Sharks

Multiple Choice

Why do skates and rays have flattened bodies, while sharks are torpedo-shaped?

A) Sharks are more closely related to the tube-like lampreys than are skates and rays.
B) Skates and rays need enlarged pectoral fins to help them stay level in turbulent water, while sharks do not.
C) Skates and rays exchange gases across their skin and thus require a high surface-area-to-volume ratio, while sharks use gills to respire.
D) Sharks are streamlined for active swimming at mid-depths, while skates move about mostly on the ocean floor.