The proteins that help defend the body against bacteria, toxins, and allergens are called antibodies. The antibody<span> (Ab) protein is also known as an immunoglobulin (Ig).
</span>These<span> large Y-shaped proteins are</span><span> produced by the immune system in order to prevent the body in response to the presence of a foreign substance. The foreign substance is called antigen.
</span>
D Bc I just did it and got it right
I've learned that the circulatory system is responsible for transporting nutrients and blood throughout the entire body :D
