For what is $D.J. Ivanowsky$ famous?

Which of the following statements is true for viruses?

What do the terms phycobiont and mycobiont signify?

Assertion $(S)$: Viruses are considered as a link between living and non-living organisms.
Reason $(R)$: Viruses replicate only when they are inside a host cell,whereas they behave as non-living particles in a free state.

Which structure in lichens produces sexual reproductive organs?

The viruses responsible for causing polio and hydrophobia are