What are some of the natural defenses that human bodies have to keep pathogens out?
a. cilia, tears, and skin
b. cilia, skin, and clothing
c. antibiotics, vaccines, clothing
d. skin, eyelashes, and vaccines

Ana is a hospital researcher. she wants to preserve organs for further study in a chemical that is called formalin. prior topreserving the organs, ana wants to familiarize herself with the hazards of using formalin. ana should consult formalin'sa. materials safety data sheet.b. date of expiration.c. date of manufacture,d. additional laboratory uses,