The virus responsible for lysogenic growth cycle is

From which plants did $D.J. Ivanowsky$ discover viruses?

Reindeer moss is

Which of the following represents the composition of a virus?

Which organisms are sensitive to $SO_2$ pollution?

$T. O.$ Diener discovered a new infectious agent that was smaller than viruses and has the following characteristics:
$(i)$ It causes potato spindle tuber disease.
$(ii)$ It has free $RNA$.
$(iii)$ The molecular weight of $RNA$ is low.
Identify the infectious agent.