What affects the freezing point of a solution more—the concentration or the identity of the solute?

Idon’t understand this page, can someone ?

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 substance can be broken down by chemical means