Answer:
Chlorofluorocarbons from the air conditioners !
Explanation:
Answer:
There are several tectonic provinces collectively called as crystalline providences.
Explanation:
- The geology of Appalachians consists of Blue Ridge, Piedmont, Adirondack, and the New England providences. They are known as Crystalline provinces.
- The sinking of the oceans continued about 270 million year ago due to which a huge mass of rocks was pushed westwards along the margins of North America and piled up to form the mountains.
- The Sierra Nevada is the youngest mountain range on the west coast of the United States.
