Lymph nodes swelling indicates they are doing their filtration job.

• A. They are fighting infection by filtering pathogens
• B. They are signaling an autoimmune disorder
• C. They have no relation to infection
• D. They are swelling due to dehydration

Answer: (A)

Swollen lymph nodes reflect active immune surveillance. Lymph nodes filter lymph to trap bacteria, viruses, and other pathogens. When pathogens are detected, immune cells inside the node proliferate and become highly active to fight the infection, causing the node to enlarge. This shows the nodes are performing their job of filtering and mounting a defense. While autoimmune-related swelling can occur, and dehydration isn’t a typical cause of lymph node enlargement, the situation described aligns with infection-fighting activity through filtration.