Most common oncogenic RNA virus?

Ans. is 'a' i.e., Retrovirus All oncogenic RNA viruses belong to family retroviridae. However it should be kept in the mind that all retroviruses are not oncogenic. The family retroviridae is classified into three subfamilies :? a) Oncovirinae : Comprising all oncogenic RNA viruses, therefore formerly it was called oncornavirus (i e. onco-RNA-virus). b) Spumavirinae : Containing non-oncogenic 'foamy viruses' causing infection in animal species. c) Lentivirinae : Including the viruses causing 'slow infections' in animals, as well as the human.