Many renewable energy sources are intermittent. what does this mean, and why does it pose a challenge to the use of these sources for electrical power generation

Explanation:

Many intermittent

Intermittent renewable energy sources which are intermittent are difficult and challenging which means that they have an disrupting effect on the conventional procedures used to plan the daily maintenance and operations      of the electric grid. The power fluctuates over different and many time horizons which will force the operators to adjust it before time  i.e an hour ahead to day ahead to adjust the operating procedures manually.  

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

answer; i believe the correct answer is (anemia);