Question

which line of defense blocks the invasion of microbes into the body?
first line
second line
third line
fourth line
question 2
2.5 pts
which line of defense provides long term immunity?
first line
second line
third line
fourth line

Explanation:

Question 1

The first line of defense (like skin, mucous membranes) acts as a physical/chemical barrier to block microbes from entering the body. The second line is non - specific internal defense (inflammation, phagocytes), the third is specific adaptive immunity (not for initial block), and there's no fourth main line of defense in standard immunity concepts.

The third line of defense (adaptive immunity with B and T cells) creates memory cells, providing long - term immunity. The first line is a barrier, the second is non - specific internal defense, and there's no fourth main line.

Answer:

A. first line

Question 2