Question

a protein molecule that the body identifies as foreign, triggering the immune response is a(n)

antibody

antigen

thrombocyte

allergy

Explanation:

• An antibody is a protein produced by the immune system to target foreign substances, not the foreign substance itself.
• An antigen is defined as a foreign molecule (often a protein) that the immune system recognizes, triggering an immune response.
• A thrombocyte is a platelet, involved in blood clotting, not immune response triggering.
• An allergy is an overactive immune response to a substance, not the substance itself.

Answer:

antigen.