Which change is more difficult to reverse, chemical or physical?

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

first thing first of the answer is with technology. second thing second thing is that the big bang theory did not happened u see they say it did but what they dont realize is that like dinasures are still a round they might deny it but they and look at these 12 foot human skelteons they find lets see didnt the bible say something about giants. hope this peace.