<prompt> Course of a disease process without any intervention is the definition ofSpectrum of diseaseEpidemiology of diseaseNatural history of diseaseIceberg Phenomenon  <response>: Natural history of disease refers to the progression of a disease process in an individual over time, in the absence of treatment Spectrum of disease signifies that the health of an individual is not static Ref : Parks Textbook of Preventive and Social Medicine; 23rd edition - Pgno. 34 