Immune system

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Across
  1. 3. single-celled organisms that thrive in diverse environments.
  2. 5. the condition of being sick or diseased; illness.
  3. 6. "a state of complete physical, mental, and social well-being and not merely the absence of disease"
Down
  1. 1. is the ability of the body to defend itself from 'foreign bodies'.
  2. 2. A product that stimulates a person's immune system.
  3. 4. a protein produced by the body's immune system