In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

[EX Q]: Question: David turns down the temperature in the cabin, so energy of sound waves is moving 
 Answer: slower
[EX A]: At a lower temperature, particles of the medium are moving more slowly, so it takes them longer to transfer the energy of the sound waves.

[EX Q]: Question: Rick had a rock (Rock A) from 1000 feet beneath the crust's surface. He later dug 3000 feet deeper and got a second rock (Rock B). Which rock is likely older? 
 Answer: Rock B
[EX A]: Older rocks are at the bottom and younger rocks are at the top.

[EX Q]: Question: John kicks the ball on a rough surface. Compared to traveling on a smooth surface, the ball travels 
 Answer: slower.
[EX A]:
The smoother the surface, the less friction against an object, so the faster it will move.