How does a vaccine help build immunity ? Describe the process of what happens in your body? I NEED IT NOW ITS FOR A TEST PLS :(

Which is not a likely outcome after extensive irrigation of dry farmland? useless, unproductive soil salinization of the soil depletion of groundwater nutrient-rich soil

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

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.