The body can be described as having three distinct lines of defense; first, second, and third. Describe one component of one of these categories (first, second, or third line of defense) and how it helps the body ward off pathogens.
The body can be described as having three distinct lines of defense; first, second, and third. Describe one component of one of these categories (first, second, or third line of defense) and how it helps the body ward off pathogens.