Adenoids - Glands that grow at the top of the throat in the back of the nose. Antibody - A substance made by the blood that destroys or weakens germs.
Antibodies help protect the body against certain diseases.
Appendix - A thin growth shaped like a bag or pouch. It is attached to the large intestine. Bacteria - Very tiny plants that are so small they can only be seen through a powerful microscope. Some bacteria cause disease, but others are helpful. Boil - A red swelling beneath the skin.