The debate regarding viruses continue. according to this passage, some consider viruses to be alive because they?

viruses are considered alive because they can make copies of themselves in a hosts cells

Explanation:

Viruses are considered as living and non - living things. They are living because when they come in contact with any host, they invade the host body.

Many viruses are acted as parasites and causes different viral diseases. The common cold is an example of a viral disease.  

On the other hand, viruses remain like the dead. They cannot reproduce without a host.  

They are present on the earth from a very early time. These always float in the air and present almost everywhere. When a suitable host is there, they dwell in its body and start to replicate. But it does many harms to the host.

These characters always make viruses a controversial microbe.