13. Which of the following is not part of the second line of defense?
a. pH of the skin
b. Cytokines
c. Phagocytosis
d. Fever

14. Cells infected with a virus produce glycoproteins that interfere with viral replication and impede its spread; these glycoproteins are called
a. interferons.
b. suppressors.
c. pyrogens.
d. prostaglandins.

15. The first line of defense that prevents microbes from entering the body includes
a. phagocytes.
b. T lymphocytes.
c. skin.
d. interferons.