ANATOMY

Detailed explanation-1: -Answer and Explanation: Fever is not the first line of defense; it is considered the second line of defense. Suppose the first line of defense couldn’t protect the body, and the pathogen still enters the body. In that case, the second line of defense protects the body, including fever, inflammation, and phagocytosis.

Detailed explanation-2: -Found in your blood and lymph system, IgM antibodies act as the first line of defense against infections. They also play a large role in immune regulation.

Detailed explanation-3: -Physical barrier The innate immune system provides the first line of defense, which is divided broadly into two categories – physical/chemical barriers and nonspecific resistance.

Detailed explanation-4: -Skin is a barrier that serves as one of the body’s first lines of defense against harmful microbes. Specialized immune cells within skin tissue help to fight invading organisms.