In a coho study nonsmokers were found to have carcinoma lung. This indicates -

Ans. is 'b' i.e., Etiology for lung Ca is multifactorialo Smoking is not specific for lung cancer becausei) Not everyone who developed lung cancer has smoked --> Other etiological factors (other than smoking) are also involved in causation of lung cancer, i.e., etiology of lung Ca is multifactorial.Not everyone who smoke develops lung cancer.