Verified answer

Viruses are constantly mutating.

Many of these mutations are less virulent than the original and fade away.

Some make so little difference we barely notice their existence.

Occasionally they are more virulent, as this one is, so spread rapidly.

These mutations first occur in a single cell replicating the virus in a host. In this case the host happens to have been a human patient infected with Covid-19.

Evolution is a process of mutations that, for the most, are ineffective or failures,  but sometimes something works better and therefore survives. 

You are a variant of human.  All of us are. 

Neither... the mutation, mutated inside of a human.