Lymph nodes are defined as what?

• A. Small structures that filter lymph fluid and contain immune cells that help combat infections
• B. Tiny glands that produce hormones
• C. Blood vessels that carry lymph
• D. Cells that break down bacteria in the stomach

Answer: (A)

Lymph nodes are small, bean-shaped structures that filter lymph fluid as it passes through and contain immune cells that help combat infections. They act as checkpoints where immune surveillance happens—immune cells like lymphocytes and macrophages scan for pathogens and initiate responses when needed. That clarifies why this description fits best. The other options describe different tissues or roles: glands that produce hormones are endocrine glands, not lymph nodes; lymphatic vessels carry lymph but are not the nodes themselves; and stomach bacteria-breaking cells refer to gastric immune defenses, not lymph nodes.