4.
(1 pt)
If gravity always pushes down, what prevents a person from sinking down into the ground?
A.
Nothing prevents a person from sinking into the ground.
B.
Gravity only pushes with enough downward force to let a person touch the ground.
C.
A person's body is pushing up, balancing the downward force from gravity.
D.
The earth is pushing up on a person, balancing the downward force from gravity.