The ratio of the risk of disease in exposed individuals to the risk of disease in nonexposed individuals is called:

What type of weather does tropical continental air bring in summer? hot and cloudy cool and sunny hot and sunny cool and cloudy

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?