Forces that are equal in size but opposite in direction are

The correct answer is balanced force.

Explanation:

Balanced forces are balanced when the forces are acting equal in magnitude but opposite in direction. The balanced forces will not cause change in the speed of the object.

Unbalanced forces are unbalanced when the forces acting on the object are not equal in magnitude. The combined force is the difference between the forces. It will cause the change in the speed of the body.

Therefore, forces that are equal in size but opposite in direction are balanced.

c because the action was the roller coaster reaches bottom of hill (action) reaction would be blood tends to drain away from head

hope this !

come closer and become far apart and become steam/gas