Which of the following statements is incorrect?

detailed solution

Correct option is D

A virus is a nucleoprotein and the genetic material is infectious. Viruses contain genetic material, that could be either RNA or DNA. No virus contains both RNA and DNA. Viruses are obligate parasites.In modern medicine certain infectious neurological diseases were found to be transmitted by an agent consisting of abnormally folded protein. The agent was similar in size to viruses. These agents were called prions.In 1971, T.O. Diener discovered a new infectious agent that was smaller than viruses and caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid.