Me with this practice options are: 1st blank: a. second b. first c. third 2nd blank: a. adaptive b. innate c. acquired

Discussion

The first thing the immune system does is prevent the invader from getting in in the first place. If the infection/virus/bacteria can't get in to start with, it can't do any damage.

The second thing the immune system does is once in, the bacteria (especially) can be hunted down and destroyed. Viruses are a little harder to deal with. But some of them can be stopped as well.

It is the third thing that a fever is employed to fight off the invaders although when a person gets a fever, he hardly thinks it is a defense mechanism. However the intent is to make the environment as uncomfortable as possible for the invader: the fever is meant to make the invader inactive.

I think it is innate. When all else fails, make the enemy a blob. Step two could have been a learned immunity. "I've seen this bug before, and he is mine." An acquired immunity would be something like an inoculation.