Final answer:
The body's second line of defense involves inflammation and phagocytosis by nonspecific leukocytes.
Step-by-step explanation:
The body's second line of defense includes the inflammatory response and phagocytosis by nonspecific leukocytes. When pathogens breach the protective barriers of the first line of defense, inflammation is triggered, creating a physical barrier against the spread of infection and repairing tissue damage. Inflammation is caused by chemicals such as cytokines and histamines, resulting in swelling, redness, and warmth. The complement system is also activated, consisting of proteins that disrupt the cell membrane of pathogens and burst their cells.