which microorganisms is the connecting link of living and non living organisms. Why ?

Dear Student,

Viruses are considered as the connecting link between the living and non-living.

Viruses are non-living when they are outside the host cell as they don't have any cellular machinery of their own. But when they are present inside the body of a host, they are living. They take over the host cell machinery to replicate themselves, killing the host. That's why they are considered as borderline between living and non-living.

Regards