Westward Expansion - Your mission

In pairs or alone according to your teacher's instructions, write an audioguide in 80-100 words.
Now, using the visual details from the painting Westward the Course of Empire Takes Its Way and the highlighted elements from the article "What is Westward Expansion?," write the script of a short audioguide for that painting, explaining:
a. To what extent it helps understand the justification of Westward Expansion.
or
b. To what extent it depicts the Manifest Destiny of the USA.

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Toolbox
First of all ...
First and foremost ...
Then ...
Besides ...
Moreover ...
Finally ...
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