"Net force" simply means the sum of all forces. The "unless acted upon by a net force" version is more correct. For example, as you stand or sit still, the earth pushes you up with a force equal and opposite to the force with which gravity pulls you down. The net force, or total force, is zero, so you do not move.
Answer:
Well, the coriolis effect is an invisible force that deflects the wind. In the northern hemisphere, winds blow to the right, and in the southern hemisphere, they blow to the left. Without this force, the tropics would be much hotter, and the poles much colder than they are today.
Explanation: