AnsweR
D
Explanation:
beaker B becz of increased surface area
Answer:
Explanation: "Warming up and cooling down are good for your exercise performance — you’ll do better, faster, stronger — and for your heart since the increased work on the heart ‘steps up’ with exercise,” said Richard Stein, M.D., professor of cardiology.
That would be known as the rifling. Helps to make the gun shoot accurately.