How does the erosion of these mountains support the principle of uniformitarianism

Erosion has looked the same way throughout Earth's history this is the erosion of the mountains supports the principle of uniformitarianism. In geology, uniformitarianism is the notion that Earth's physical shape is the end result of currently existing forces that have operated uniformly (in an identical way) since Earth shaped the kind of 4.5 billion years in the past.

What are two ways that scientists can study Earth's climate history?