1. affects the straight-line motion of a flying object by pulling it
down toward the ground.
A Buoyancy
B. Density
C. Gravity
D. Pressure

Gravity

Explanation:
-Gravity is the force that attracts a body toward the center of the earth, or toward any other physical body having mass.

-Gravity does not affect horizontal motion, it only affects vertical motion and it acceleration going downward. Air resistance is what’s going to affect your projectiles horizontal motion going forward.

In general, the greater the degree of undercooling of a liquid melt, the smaller the critical radius of the nuclei formed.