Answer:
The immune (ih-MYOON) system attacks germs and helps keep us healthy. What Are the Parts of the Immune System? ... White blood cells, also called leukocytes (LOO-kuh-sytes), play an important role in the immune ... That way, if the immune system encounters that antigen again, the antibodies are ready to do their job
Explanation:
Answer:
<h2><em><u>C. Incident.</u></em></h2>
Explanation:
Incidents surprise people, causing then to jump. This happened even when the incident did not actually cause any pain for the person. Hope this helps!
There were more but they weren't discovered as they were not viral and treatment was unknown and research were not done.
I believe the answer is the systemic circuit
