Complex sentence: A dolphin can make two to 5.5 spins in one leap; the swimming and rotational speed of the dolphin as it spins underwater affects the number of spins it can do while airborne.
Split into simpler sentences: A dolphin can make two to 5.5 spins in one leap. The swimming and rotational speed of the dolphin spinning underwater affects the number of spins it can do while airborne.