What did each of these african american legislators have in common?

Why were the numbering trials held from 1945 to 1946 ?

During the cold war, the united states was involved in certain regional conflicts due to fears later called the domino theory, which stated which concept?

The 20th amendment, also called the lame duck amendment, decreased the amount of time between the presidential election and the inaugration of the new president. what are the advancements that allowed for this amendment?