Question

a boy on a skateboard is rolling along a flat, paved sidewalk. his skateboard hits a patch of sand, and he slows down. which phrase best explains what causes the skateboard to slow down? mass of the sand mass of the skateboard increased friction from the sand increased gravity on the skateboard

Explanation:

Friction opposes motion. Sand creates more resistance than the paved surface, causing the skateboard to slow down. Mass of sand or skateboard doesn't directly slow it down, and gravity remains constant in this scenario.

Answer:

increased friction from the sand