Immune system? Researchers believe that the appendix does serve a function as part of the immune system. Others feel that the appendix is a vestigial organ, once used as part of digestive process.
No to my knowledge. I do not believe that there is a well accepted purpose for the appendix. It is possible that evolutionarily there may once have been a purpose.
May be. A physiologic role for appendix has not been determined. It may serve as a source of lymphocytes if other sites were to get selectively depleted, may be.