Which features help reduce the amount of runoff that occurs in an area?

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems

The open ocean of any depth is called the

Part of the elbow is formed by the end of the humerus. what do you call this part?