Final answer:
The Appalachian Mountains were formed around 300 million years ago (3.0 x 10⁸ years) through a series of tectonic events, including continental collision between Africa, Europe, and North America.
Step-by-step explanation:
The Appalachian Mountains formed approximately 300 million years ago, which in scientific notation is written as 3.0 x 10⁸ years. This mountain range is the result of several orogenic events, the most notable being the Taconic, Acadian, and Alleghenian orogenies. During these events, the continents of Africa and Europe collided with the North American plate, leading to the uplift and subsequent erosion, reshaping the landscape into what we see today, such as the distinct physiographic provinces within the Great Smoky Mountains National Park.
The physical geography of a region, including mountain building through tectonic activities like continental collision, is a foundational concept in understanding how features such as the Appalachian Mountains are formed. It also connects to broader geological concepts like isostasy and the creation of foreland basins, similar to those which formed the Persian Gulf and Baffin Bay.