Which of these is a physical property of wood?
a. wood can burn.
b. wood can rot.
c. wood does not rust.
d. wood is softer than coal.

trig 15.3 cos

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.