Why is it necessary to research your experiment before starting it?

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.

Consider the story you just read. all but one of the choices below indicate that something is living.

The point along a planet's orbit where it is closest to the sun is called the