14. what was the name given to the idea that if vietnam fell to communism, the rest of southeast asia would become communist? a. the roll back theory b. the communist theory c. the domino theory d. the steamroller theory

This is called the domino theory (answer C).

This is because in a domino game, you can place the domino pieces next to each other and if you push only one, all of them will fall. So similarly, people believed that if just one country in the area fell to communism, all of them would also do the same as the result.

3. i would say one, but one is not prime nor composite.