Question

which of the following statements concerning immunity is correct?
multiple choice
adaptive immunity demonstrates memory, meaning each lymphocyte responds to a particular pathogen, but responds similarly with each infection.
all of the choices are correct.
adaptive immunity demonstrates specificity, which means that lymphocytes only destroy viruses and ignore all other types of pathogens.
adaptive immunity responses to pathogens improves over time due to generation of memory, which includes an increase in the number of lymphocytes that respond faster than during the original infection.

Explanation:

• Option 1: Adaptive immunity does have memory, but it doesn't mean "responds similarly with each infection". The second - exposure response is faster and stronger.
• Option 2: Since option 1 and 3 are incorrect, "All of the choices are correct" is wrong.
• Option 3: Specificity in adaptive immunity means lymphocytes respond to a particular pathogen (not just viruses).
• Option 4: Adaptive immunity has memory. Memory lymphocytes are generated. During a secondary infection, these memory lymphocytes respond faster and in greater numbers than during the primary (original) infection.

Answer:

Adaptive immunity responses to pathogens improves over time due to generation of memory, which includes an increase in the number of lymphocytes that respond faster than during the original infection.