correct the text by inserting two commas. (note: in this skill, serial commas are not optional.) the united…

Brief Explanations:

The sentence needs commas to separate the main - clause and the non - essential clause. "The United States is not the only country with a red, white and blue flag" is the main idea, and "the flags of over thirty other nations use the same colors" is additional information.

Answer:

The United States is not the only country with a red, white, and blue flag; the flags of over thirty other nations use the same colors.