Answer #1:
The domino Theory is a theory that effect the time line of reality.
Explanation #1:
Imagine a line of domino's, the first domino is one action doing something and each domino is a different action that would happen because of the action that came before it. knock one domino down the rest gets knocked down, cause one action other actions will happens in result of the first action
Answer #2 & Explanation #2
The government was afraid of countries turning communist because they thought the domino affect was in order, which would lead to the other countries turning communist.