How to tell if someone is in rem sleep or deep sleep?

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

In what ways does the study of human population differ from the study of wildlife ecology

Which two molecules generated by the krebs cycle pass their high-energy electrons to the electron transport chain? a. nadh b. c6h12o6 c. fadh2 d. nad+