Available choices:
a). ability to sense light.
b). principals of aerodynamics.
c). kinetic energy.
d). swimming slower.
e). refraction of light.
f). poor swiming.
g). bending light rays.
h). dynamic relationships.

Fact 1: Webbed feet are used for moving faster through water by aquatic animals. Fact 2: Aquatic animals moving through water are also subject to the principles of aerodynamics. Given the two facts above, aquatic animals in water use webbed feet due to what?
Answer:
b).