Which of these is not part of the body's immune system?
a. antibodies
b. memory cells
c. red blood cells
d. white blood cells

Andrew loves to go camping and hiking in the fall. about two weeks after his last camping trip, he noticed an expanding red, target shaped, rash on his arm. to avoid this illness, andrew should have select one: a. boiled his water before drinking. b. avoided contact with ticks. c. avoided contact with fleas found on mice. d. camped only in the spring.