is root a virus

You can't, and don't. Root is the Unix base of the OS itself. It's supposed to be there. Ignore it.

No.

A virus in a Mac can not exist. Period. Let me explain why. You question whether whether a Mac can be infected by a virus. When Apple released Catalina, we can now see (using the Disk Utility app) three icons if we click on the Container disk icon. One is titled Macintosh HD and the second one is titled Macintosh HD - Data. What does this mean? the first one, Macintosh HD, is where our Apple installed apps and files is contained. This is a read only disk. That means that no outside files can be written on it. Therefore, no viruses. It is protected from infection. The second Macintosh HD - Data is where our installed apps are located. This allows us to remove and install apps. Last, Apple has its own anti-virus app which is part of our operating system. This is an incredible way to ensure that the Mac OS is the most secure one in the industry. I hope this puts your mind at ease.