Which correctly describes the projected growth of the world's population in the future?
A. The rate of growth will remain the same.
B. It will not grow much higher than it is now.
C. The population will eventually begin declining.
D. The rate of growth will slow down by 2100.

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on