Why are there more coal in the eastern US than the western US

Coal is the largest source of energy for generating electricity in the world, and the most abundant fossil fuel in the United States. Fossil fuels are formed from the remains of ancient organisms. Because coal takes millions of years to develop and there is a limited amount of it, it is a nonrenewable resource

Explanation:

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.