CNA Practice Test
Body systemsQuestion 790 of 1700

Which is a specific defense of the immune system?

  1. The skin that covers the body
  2. Mucous membranes that line the body
  3. Red blood cells that carry oxygen
  4. White blood cells in the blood
Show answer

Correct answer: White blood cells in the blood

White blood cells identify and destroy pathogens.

Source: Nursing Assistant (Reuter), 11.9: Immune System

Practice body systems

Questions last reviewed: 18 October 2026