Which scientist demonstrated that the extract of infected tobacco plants could cause infection in healthy plants?

Which organism is formed by the symbiotic association between algae and fungi?

What is a virus?

The protective coat of structural protein in a virus is made up of units called:

Read the following statements carefully and identify correct statements $w.r.t.$ Lichens:
$a.$ The association cannot tolerate air pollution,especially due to sulphur dioxide.
$b.$ Lichens are annuals and their growth is slow.
$c.$ The fungal partner mostly belongs to Ascomycetes.
$d.$ Soredia are most efficient means of asexual reproduction.
$e.$ Orchids seldom occur without this association.
$f.$ Foliose lichens are pioneers of succession in a water body.

Which of the following viruses contains $RNA$ as its genetic material?