21. The Immune System

Skin and mucous membranes are mostly involved in:

The 1st line of defense that the body uses to prevent infection includes?

A patient consumed food contaminated with pathogenic bacteria. However, the patient did not become ill. The doctor explained to the patient that the acidity of the patient’s stomach can kill many organisms, including bacteria. This type of protection would be classified as?

Antibodies are a part of which type of immunity and why?