Circularity system........…….......
It’s gonna be Oxygen ....
see i was trying to figure out the answer but i didn't understand it so i took the time to research and work it out but i still didn't understand i found one that was close to it and i got the same one as the other person which is D but idk if it is that type of question if it is than it is d if not then idk
Answer:
The water acts like a lubricant therefore has a smooth motion over the ice.