 If Black has played the Slav move order (2...c6), then after the recapture cxd5 ("exchange Slav") the pawn structure is symmetrical.Should Black have played 2...e6 instead, the recapture exd5 leads to an imbalanced pawn structure called the Carlsbad structure, which might offer White some opportunities for a minority attack on the queenside.Protecting the d5-pawn with the c-pawn has at least three implications for Black.