Lumbago with sciatica, left side: ________

When ventilating a multistory building, it is best to apply positive-pressure ventilation (PPV):

A. on the floor with the least smoke. B. on the floor with the most smoke. C. at the highest point of the structure. D. at the lowest point of the structure.

The overreaction of the immune system to a substance that is otherwise harmless is known as:

a. hypersensitivity. b. hives. c. anaphylaxis. d. immunity.