Which disease in tobacco was identified by $D.J. Ivanowsky$ as being caused by viruses?

The protein coat called capsid,made of small subunits called capsomeres,is present in:

What is the function of the algal component in a lichen?

Select the wrong statements.

Choose the correct option for the following statements:
$(i)$ The name virus,meaning venom or poisonous fluid,was given by $Pasteur / D. J. Ivanowsky$.
$(ii)$ $W. M. Stanley / T. O. Diener$ discovered viroids.

$A$ scientist $X$ demonstrated that the extract of infected plants of $Y$ could cause infection in healthy plants and called the fluid as "Contagium vivum fluidum". Identify $X$ and $Y$.