A passing grade is a grade that makes a person eligible to go to the next grade.
The answer is "night sky"
hope i helped :)
BAS might be an improperly capitalized: BAs, BaS
PTF2 might be an improperly capitalized: PtF2
BAF2 might be an improperly capitalized: BaF2
PTS might be an improperly capitalized: PtS