What beats a bishop in chess?

What beats a bishop in chess? A rook is generally worth about two pawns more than a bishop (see Chess piece relative value and the exchange). The bishop has access to only half of the squares on the board, whereas all squares of the board are accessible to the rook.

A rook is generally worth about two pawns more than a bishop (see Chess piece relative value and the exchange). The bishop has access to only half of the squares on the board, whereas all squares of the board are accessible to the rook.