事实证明，这种药物（最好了解它的通用名：萨力多胺）会引起上千出生在欧洲的新生儿生来无肢或肢体发育畸形。

As it turned out, the drug (better known by its generic name, thalidomide) would cause thousands of children in Europe to be born limbless or wi flipperlike arms and legs.

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这张图片来自费城穆特博物馆的收藏，展示一位无肢畸形的小姑娘，这一种疾病的特点是四肢未充分发育。

This image, from a collection at Philadelphia's Mutter Museum, shows a young girl with amelia, a condition marked by undeveloped limbs.

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但是，哪种具有四肢的近亲及其特征导致了向无四肢的蛇的进化呢？

But which four-legged relatives and their family traits led the transition for legless snakes?

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