What are the general functions of the major systems of the human body?

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

Decreased sensitivity to an unchanging stimulus is known as

If a car is traveling on the highway at a constant velocity, the force that pushes the car forward must be a. equal to the weight of the car. b. less than the force of friction exerted upon the car. c. equal to the force of friction exerted upon the car. d. greater than the weight of the car.