【待插入句子】One of the major effects was the rapid growth of the human population itself.

【待插入段落】Paragraph 1: The universal global warming at the end of the Ice Age had dramatic effects on temperate regions of Asia, Europe, and North America. Ice sheets retreated and sea levels rose. ■The climatic changes in southwestern Asia were more subtle, in that they involved shifts in mountain snow lines, rainfall patterns, and vegetation cover. ■However, these same cycles of change had momentous impacts on the sparse human populations of the region. ■At the end of the Ice Age, no more than a few thousand foragers lived along the eastern Mediterranean coast, in the Jordan and Euphrates valleys. Within 2,000 years, the human population of the region numbered in the tens of thousands, all as a result of village life and farming. ■Thanks to new environmental and archaeological discoveries, we now know something about this remarkable change in local life.

正确答案为3rd square;

2.插入句子说 重大影响中的一个是：快速增长的人口。那么一定要跟在major effects后面，而我们看到了段落中的momentous impacts;完美的paraphrase，所以毫无疑问就是这里了。

再看段落，组成也很明确：1st为TS主旨句——全球变暖对于各洲的温带(temperate)区域有dramatic effcts。2nd: 西南亚的气候变化更细微。 3rd: 但是，同样的变化循环对人口稀少(sparse)的区域有巨大的影响。4th:在冰河世界末期，只有数千人。2000年间，人口成千上万的增长，都是因为乡村生活和农耕。5th：多亏了新发现，我们知道这种当地生活的剧烈变化。