T.O. Diener discovered a
- free infectious DNA
- infectious protein
- bacteriophage
- free infectious RNA
Answer
(4) free infectious RNA
Solution
As per NCERT, in 1971 T.O. Diener discovered a new infectious agent smaller than viruses that caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat found in viruses, hence the name viroid.
∴ Diener discovered a free infectious RNA (viroid).
⇒ Infectious proteins are prions; a bacteriophage is a virus infecting bacteria.
Answer: (4)