Which one of the following pollutants is responsible for the increase in skin cancer?
a. chlorine monoxide from automobiles
b. nitric oxide
c. polychlorinated hydrocarbons
d. chlorofluorocarbons

Viruses can be transmitted through air, water, food, insect bites, and direct skin contact. once a virus gains entry into the body, it invades a host cell in order to? a. synthesize antibodies for defense b. deactivate the host cell's defenses c. access cell processes for reproduction d. metabolize host proteins and grow

According to cell theory; which structures carry out the basic function of living things? a. atoms b. organs c. cells b. nuclei

Which of the following statements about brain development and early childhood is true? the brain of a 5 year old is 60 percent the size of an adult brain the overall size of the brain does not increase dramatically from ages 3-15 by the time a child is 3 years of age, the brain is 25 percent of it's adult size the development that occurs inside the brain ends at the onset of adolescence