Birds with more massive beaks, such as the one on the right, were better adapted to break these tougher seeds open, and hence were more likely to survive, while smaller-beaked birds such as the one on the left perished.
(Birds with more massive beaks, such as the one on the right; were better adapted; to break these tougher seeds open) (Birds with more massive beaks, such as the one on the right; hence were; more likely to survive) (smaller-beaked birds such as the one on the left; perished; )
Birds with more massive beaks, such as the one on the right Birds with more massive beaks, such as the one on the right smaller-beaked birds such as the one on the left
were better adapted hence were perished
to break these tougher seeds open
more likely to survive