Because to actually use the word evolve an organism must suffice more than one condition, which in this case would be an advantageous trait. Having an advantageous trait (from our eyes at least) must also include the right and stimulating enviironment for procreation. So this answer is multifolded.
Acid Rain is the problem threatening many of Europe's (most specifically Germany's) forests, lakes, and rivers. Acid rain travels via the wind and the acid pollutants can travel through this said wind to multiple countries. It was a large problem in the 1970's and 80's.
The Phleom does that action. Hope this helped! :)
What? im aorry i dont understanf