Why is it adaptive for memory cells to remain in the immune system after an invasion by pathogens?

Question

Why is it adaptive for memory cells to remain in the immune system after an invasion by pathogens?

Answer 1

Because this allows the individual to better survive a later attack, making them more likely to survive and reproduce overall.

Answer 2

As a result of memory cells, on exposure to a second infection by the pathogen the response will be quicker and stronger.

Answer 3

Your question has a built in assumptive answer.

You could ask why is it designed for the memory cells to ....

The answer about the resistance of the second attack by the similar pathogen is correct. It is quite a marvolous system. Just one of the tens or hundereds of thousands of perfectly complex systems in your body.

Thank God.