Why are the sierra nevada lakes very sensitive to changing climate?

Because the surrounding mountains contain very little soil, and nutrients are easily washed into the lakes, which could cause algae blooms and other problems. But It is not climate change, they are sensitive to different weather patterns.

B.a pop up at ion changes in response to a change in the environment.

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser