Plsss help Worth a lot of points

15) To aid their trading with Native Americans.

16) Mississippi River and St. Lawrence River

17) Fort Maurepas

18) Spain. France regained it in 1803.

19) He sold it to the United States.

20) Detroit, New Orleans, Baton Rouge

Explanation:

this defines the ability for a flex item to grow if necessary. it accepts a unitless value that serves as a proportion. it dictates what amount of the available space inside the flex container the item should take up.

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