Breathing Using complete sentences, explain how the muscular, skeletal, respiratory and circulatory systems work together to get oxygen from outside your body into your lungs.​

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

What's the question?

A. convection currents in the mantle.is the correct answer