The blood enters from the right and exits through the left!
A is the answer. This is because this was not covered by the Twin studies.
Good luck!
-RxL
1 be heard. 2. true. 3 responsible
Answer:
antibodies
Explanation:
The third line of defense is specific resistance. This system relies on antigens, which are specific substances found in foreign microbes. Most antigens are proteins that serve as the stimulus to produce an immune response. The term "antigen" comes from ANTI-body GENerating substances.