Answer:
A. A golf ball striking the ground is a collision.
B. The ground exerts an equal force on the golf ball.
Explanation:
A collision is the mutual interaction between two or more bodies, of which at least one is in motion, with an exchange of momentum and energy.
According to Newton's third law, if the golf ball exerts a force on the ground, then the ground must exert a force of equal magnitude in the opposite direction on the golf ball.
