That's an urban legend that's been around for a long time.
It was tested on "Mythbusters". The conclusion was that
it would sting pretty good, and maybe raise a lump, but
it would never penetrate the skull, and it couldn't kill.
Were the pool to be one of water, then sound would travel faster than in the air of a bedroom
He from the 10m long grass
Answer: The answers are A. Wind, B. Water, and D. Gravity.
Explanation: All four factors contribute to weathering and erosion; however, ice is not shown in the image, so it likely did not play a role in the collapse of the cliff.
(Next time please provide an image so it would be easier!)