gwd1-12这句话是什么意思啊

kevinjpcn

The author mentions the "aftermath of the Mount Saint Helens eruption" most likely in order to

• Aprovide an example of the process that allows the repopulation of rivers whose indigenous salmon population has become extinct
• Bindicate the extent to which the disturbance of salmon habitat by human activity in one stream might affect the genetic structure of salmon populations elsewhere
• Cprovide a standard of comparison against which the impact of human activity on the gene flow among salmon populations should be measured
• Dshow how salmons' homing instinct can be impaired as a result of severe environmental degradation of their natal streams
• Eshow why straying rates in salmon populations remain generally low except when spawning streams suffer severe environmental disturbance
  

其中的C选项的which指代什么啊？怎么翻译啊

麻烦大牛指点一下啊

kevinjpcn

发错了。本来想发到阅读区地，不好意思