Answer the following question: Here's a logic test: Some young kids were bored in a pool by a waterslide, and spotted a toilet paper roll. They noticed that the water on (A) the waterslide would carry the roll floating lightly above and move it smoothly, whereas the (B) grass would slow its motion quickly due to the big friction differences of these surfaces. Choose the answer between "waterslide" and "grass".
Answer:
waterslide