Sprinter set in the starting blocks at the beginning of a race rely on what kind of energy conversion

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Which tool is least in predicting weather

Aecosystem is if it can continue to function over long periods of time