All of the following measure mass except
a. milligram
b. kilogram
c. decigram
d. centimeter

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.

there are no contact forces mentioned on the list of choices that you've provided.