Dr. Burney was trying to determine the cause of a mysterio…

  Dr. Burney was trying to determine the cause of a mysterious epidemic affecting fish in the Gulf of Mexico.  He came up with an initial question asking “why are mass numbers of fish in certain areas of the Gulf of Mexico becoming ill and dying?”  His initial proposal for this question was that “deaths were caused by infection from a single-celled protist”… this tentative explanation is considered a(n) _________.