I know that Boarding Schools look for end of year transcripts as to see how you grades are. So lets say, I made a mistake in art class and get a B-, (My GPA when I applied was 3.91) and I get some other A-'s, which would potentially get me a GPA of 3.6-3.8. Now I would like to know if this could actually make admissions change their decisions?
Unlikely. However, if you got a D or an F, then you risk losing your place.
Additionally, and it may depend on the school, they are more interested in performance in core subjects (English, math, science, social studies, foreign language (if offered). Music/art/theater/PE/shop, not as much.
Okay thanks a lot 
also much love for answering my other post 
Also, try not to commit a felony.
Drugs, alcohol, academic dishonesty.
@ChoatieMom My history teacher worries about kids stealing her pencils.
Your history teacher is right to worry : Stealing pencils is a gateway crime.
Hate it when people steal my pencils after I let them borrow them.
Eating a hedgehog whilst throwing eggs at the headmaster? or vice versa?