Q: Each antibody can bind with just one specific type of what, resulting in a signal for a phagocyte to destroy them?


Read this paragraph and choose the correct option from the provided answers:

B cells respond to pathogens and other cells from outside the body in the blood and lymph. Most B cells fight infections by making antibodies. An antibody is a large, Y-shaped protein that binds to an antigen , a protein that is recognized as foreign. Antigens are found on the outside of bacteria, viruses and other foreign microorganisms. Each antibody can bind with just one specific type of antigen ( Figure below ). They fit together like a lock and key. Once an antigen and antibody bind together, they signal for a phagocyte to destroy them. Phagocytes are white blood cells that engulf targeted antigens by phagocytosis. As the antigen is on the outside of a pathogen, the pathogen is destroyed by this process.

 Choices:

- pathogen

- adhesion

- immunogen

- antigen


A:
antigen