Explanation: Insidious is often used to describe something that usually seems harmless or inoffensive, but that actually causes great harm or a terrible effect. In the given case, the word "insidious" is used before the word "disease" and this two words describes the word "racism", so, in this context, the word insidious have the meaning of something that is very harmful.
If for whatever reason we are forced to leave Earth there are no other hospitable planets we could live on. By making mars more like Earth we could eventually relocate to mars.
