Answer:
It may change structure do to human activity.
Explanation:
The Rocky Mountains are described as younger because the Rocky's are really two mountain chains. The older mountain chain started billions of years ago, and the younger mountain chain pushed the older mountain chain up more, only 60 millions years ago.
The most active volcanoes are located in South America and the bottom of North America
Because:
Its far away.
The farther an object it is, the smaller it is.