What are malignant tumors?
a. tumors that grow slowly and do not spread from their original site
b. tumors that grow fast and spread to neighboring tissues
c. tumors that start in blood forming tissue and produce abnormal blood cells

Active immunity refers to: a. the defenses people are born with. b. temporary immunity granted from another source. c. immunity gained through immunization and exposure to diseases. d. natural immunities that protect humans from other animal diseases