Which organism has a nerve net that allows it to respond to a stimulus in a coordinated way? a.) clam b.) shark c.)hydra d.)earthworm

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.