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下面为大家推荐的是一篇SAT文章阅读模拟题的相关内容，后面附有题目正确答案。这是一篇关于embryo cells 的SAT阅读文章，篇幅不是很长，题目量也不大。下面大家就和小编一起来看看这篇模拟题的详细内容吧。 Nearly a century ago, biologists found that if they separated an invertebrate animal embryo into two parts at an early stage of its life, it would survive and develop as two normal embryos. This led them to believe that the cells in the early embryo are undetermined in the sense that each cell has the potential to develop in a variety of different ways. Later biologists found that the situation was not so simple. It matters in which plane the embryo is cut. If it is cut in a plane different from the one used by the early investigators, it will not form two whole embryos. A debate arose over what exactly was happening. Which embryo cells are determined, just when do they- become irreversibly committed to their fates, and what are the morphogenetic determinants that tell a cell what to become? But the debate could not be resolved because no one was able to ask the crucial questions in a form in which they could be pursued productively. Recent discoveries in molecular biology, however, have opened up prospects for a resolution of the debate. Now investigators think they know at least some of the molecules that act as morphogenetic determinants in early development. They have been able o show that, in a sense, cell determination begins even before an egg is fertilized. | 
