Which of the statements are correct with respect to viroids?
I. T. O. Diener discovered a new infectious RNA, smaller than viruses.
II. Molecular weight of RNA is high.
III. Causes potato spindle tuber disease.
IV. Are infectious protein particles.
V. Causes mad cow disease.

Q. Read the given statements that describe certain infectious particle.
(i) It was discovered by T.O. Diener and was found to be smaller than viruses.
(ii) It causes potato spindle tuber disease.
(iii) It is a free RNA particle which lacks the protein coat.
(iv) It has low molecular weight RNA as genetic material.
Which of the following is referred to here?

Q. Which among the following is correct?

A.	Viroids	Infectious free RNA	Potato spindle tuber disease
B.	Prions	Infectious proteins	Mad cow disease
C.	Viruses	Nucleo proteins	Mumps
D.	Lichens	Algae + Fungi	Indicators of CO pollution

Q. Read the following statements and select the option which identify the incorrect ones:
(i) Potato spindle tuber disease and Chrysanthemum stunt disease are caused by viroids.
(ii) $T_4$ bacteriophage exhibits lytic cycle.
(iii) Retroviruses have two copies of ssRNA.
(iv) Interferon which prevent viral multiplication are glycolipid particles.

Q. The smallest self-replicating particles are
(a) Infectious RNA particles
(b) Obligate parasites
(c) Known to cause diseases in plants, animals and fungi
(d) Devoid of protein coats
The correct option is _________

Q. T.O Diener (1971) discovered a new infectious agent that was smaller than viruses. It was