1. Fill in the blank:
The ________ of a lymphocyte results in immune cells that havegained the ability to attack specific antigens.
2. How does a virus, such as HIV, typically enter a cell? Whatstructure does the virus use to enter the cell?
3. Explain why we need the mechanisms of the adaptive immunesystem even though nonspecific or innate resistance mechanismsattack all foreign antigen (in other words, what purpose does theacquired immune system serve?)
