If there is no friction in a rollercoaster is the speed the same throughout?

If there is no friction, the roller coaster would keep moving forever but a constant velocity. The only way it would accelerate is if there was a force continually pushing on it.

No because different Surfaces have different friction and that causes a Speed difference on each surface

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.