What BEST describes the roles of photosystem I and photosystem II in the process of photosynthesis? A. They form ATP as hydrogen ions cross the thylakoid membrane. B. They absorb sunlight and distribute the energy as heat. C. They transfer electrons from a series of intermediates to form NADPH. D. They absorb sunlight and transfer the energy to electrons.

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