Final answer:
The transition word that would more logically connect the ideas expressed in sentences 4 and 5 is 'Furthermore'.
Step-by-step explanation:
The transition word that would more logically connect the ideas expressed in sentences 4 and 5 is Furthermore. This transition word would indicate that the argument continues and builds upon the previous point. It would show that the bone structures of dinosaurs being similar to reptiles, and birds being warm-blooded, are both supporting evidence for the contention that dinosaurs were cold blooded.