The play received 'mixed' reviews. = The play's reviews were 'mixed'. [=some critics liked the play, while other critics did not]
I accidentally 'mixed up' the two files. [=I put each of the files in the place where the other one should have gone]
He 'got mixed up in' a plan to destroy the government. [=he became involved in a plan to destroy the government]
(..) because the iron in the dinosaur's blood... generates free radicals, and those are highly reactive. The proteins and the cell membranes get all mixed up... and act as a natural preservative. DNA can survive for millennia that way. Even if the amber mines dry up, they'll still have bones-- Shut up. (..)2015 Jurassic World