Question

multiple choice question
adaptive immunity is part of the body’s ______ line of defense.

second

third

first

Explanation:

The body's immune system has three lines of defense. The first line (skin, mucous membranes) and second line (inflammatory response, phagocytes) are innate. Adaptive immunity (with B and T cells) is the third line, targeting specific pathogens. So adaptive immunity is the third line.

Answer:

B. third (assuming the options are labeled as first, second, third; here the correct option is the one with "third")