The body's most important nonspecific defense against pathogens is/are
a. tears.
b. mucus.
c. saliva.
d. skin.

9. wind power creates pollution. water air soil noise

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these

Which of the following human activities resulted in the growth of the north american deer population?