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Given a scientific passage and an answer, generate a question for the given answer.

Passage: The basic crocodilian body plan ( Figure below ) is a very successful one and has changed little over time. Modern species actually look very similar to their Cretaceous ancestors of 84 million years ago. All species of crocodilians have similar body structures, including an elongated snout, powerful jaws, muscular tail, large protective scales, streamlined body, and eyes and nostrils that are positioned on top of the head. Answer: top of head
Output:
All species of crocodilians have similar body structures, including an elongated snout, powerful jaws, muscular tail, large protective scales, streamlined body, and eyes and nostrils that are positioned on what?