When this inland sea retreated, Hamilton hypothesizes, the Amazon dolphins remained in the river basin, evolving into striking creatures.
哈密尔顿推测，当这片内陆海退去，亚马逊河豚在流域留了下来，逐渐进化为一种恐怖动物。
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Krebs hypothesizes that the herons in smaller flocks are watching for herons that they might follow to better feeding pools, which usually attract larger numbers of the birds.
The environmental approach hypothesizes that states appear in certain environmental settings, settings which have a severe population problem or a shortage of agricultural land.