Writing Homework Help

I’m working on a history writing question and need an explanation and answer to help me learn.

we have explored how the European settlers formed a nation state and went on to assume legal claim to all the land within the contiguous 48 states. Once again presume you are explaining to a friend from outside of class and describe for them, using specifics drawn from the readings and videos, the concept of Manifest Destiny. What is Manifest Destiny? And how did it serve as a justification for American expansionism?