Why would heating the gas in a hot air balloon make the balloon rise?

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 of the following describes the entropy change as a solution is made from a liquid and solid

What is the body’s main processing system? it uses input from various parts to control voluntary and involutiontary movement. it’s composed of two main parts-the brain and spinal cord. a. nbs b.cns c. ans d. pns