Although no one has quantified changes in the rate of straying as a result of the disturbances caused by humans, there is no reason to suspect that the effect would be qualitatively different than what was seen in the aftermath of the Mount Saint Helens eruption.
. Yet high rates of straying can be problematic because misdirected fish may interbreed with the existing stock to such a degree that any local adaptations that are present become diluted.
The trend is also evident, however, in works focusing on those middle- and upper-class European women whose ability to write gives them disproportionate representation in the historical record. Such women were, simply by virtue of their literacy, members of a tiny minority of the population,
Many recent works by these scholars stress the ways in which differences among Renaissance women—especially in terms of social status and religion—work to complicate the kinds of generalizations both Burckhardt and Kelly made on the basis of their observations about upper-class Italian women.
P：结果 sea otters in the North Pacific Ocean began to decline. seals and sea lions was almost certainly caused by a pollution-related disease,
C：原因 disease is the more likely
A； 鲸鱼没有seals and sea lions 吃了，开始吃其他食物它因削弱。
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画数轴的方法是最简单的了，但是我忘了x和y的大小也是不确定的。。。
（1），xyz的情况要么是正正负，要么是负负负；不充分
（2），xy一正一负，不充分
（1）+（2），z为正数，xy一正一负，但谁正谁负不清楚，不充分