Match each element of the immune system to the correct description of its action in the body:
a. Antigens
b. Complement system
c. Lymphocytes
d. Macrophage
e. Chemical mediators
f. Antibodies
1. Any foreign substance that initiates an immune response
2. A group of inactive chemical mediators that, when activated, stimulate the release of other chemical mediators
3. Cells that provide humoral (B lymphocytes) and cell-mediated (T lymphocytes) immunity
4. Cells that present antigens to lymphocytes to initiate specific immune responses
5. Includes kinins, histamine, prostaglandins, and chemotactic factors
6. Proteins produced by a humoral response to bind with a specific antigen