Why do countries that formerly possessed nuclear weapons , such as ukraine and south africa , may have given them up ? why do other countries such as the united states continue to have nuclear weapons ?

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?

Why have some historians rejected the labels bc and ad as laels for periods in world history

What do u think caused the size of the roman empire to change