Which statement about phagocytes is accurate?

• A. Lymphatic organs are the sole defenders.
• B. Phagocytes attack and destroy pathogens that have bypassed protective barriers.
• C. Antibodies store and transport oxygen.
• D. Complement system produces insulin.

Answer: (B)

Phagocytes are frontline cells of the innate immune system that detect, engulf, and destroy microbes that have breached the body’s initial barriers. They move to infection sites, recognize pathogens through pattern-recognition receptors, and often bind microbes via opsonins to enhance uptake. Inside the phagosome, lysosomes fuse to form a phagolysosome where ingested pathogens are killed and digested. This is precisely what happens after pathogens bypass protective barriers, so the statement that phagocytes attack and destroy those pathogens is accurate. Phagocytes also help link to the adaptive immune response by presenting antigens, but the core idea is their role in eliminating invaders that slip past barriers.

The other statements don’t fit: immune defense is not limited to lymphatic organs alone, but involves many components acting together; antibodies do not store or transport oxygen (that’s the job of red blood cells and hemoglobin); the complement system does not produce insulin (it comprises proteins that promote inflammation, opsonization, and lysis).