In the process of glycolysis, four ATP molecules are synthesized from four ADP molecules. Why does glycolysis not yield four molecules of ATP? A TWO ATP molecules are lost in the cytoplasm.
B. Two ATP molecules are converted immediately back to ADP.
C. Two ATP molecules are required to start the process.
D. Two ATP molecules are absorbed in the mitochondria

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