Final answer:
The factors affecting changes in downward motion are mass and direction of friction, and gravity is responsible for downward motion.
Explanation:
Mass (M) and direction of friction are two factors that affect the effect of changes in downward motion. The force of gravity is responsible for the downward motion of a person or object on Earth's surface.
Learn more about forces affecting downward motion here:
https://brainly.com/question/31026314
