Give your life to Jesus Christ before its to late dont go to Hell go to Heaven

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes

All other things being equal the size of a population will decrease if