![Image](https://images.theconversation.com/files/321827/original/file-20200320-22594-njgrpz.png)
evolution happens when 1) there is variation that is 2) heritable and 3) confers a relative advantage that results in more genetic information being passed to future generations from those with the beneficial variation, than those without the beneficial variation
beneficial variations in viruses most often are 1) host immune system evasion, and 2) greater transmissibility (among other things)
it’s obvious if you aren't a snowflake of conspiracy monger