Which is true of stacking structures? two incidences of the same structure cannot be stacked adjacently. when you stack structures, you cannot nest them in the same program. each structure has only one point where it can be stacked on top of another when you stack structures, the top structure must be a sequence.

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