What happens to air when it is heated by the sun? A. water vapor changes to liquid
B. it descends
C. it rains
D. it rises

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