All of the mentioned things were a direct consequence of World War I. After the end of WWI the Austro-Hungarian empire collapsed, new nation-states were created and Germany lost all its colonies - these are exactly the same things that were asked in your question.
Answer: A session is a regular period of time where congress conducts their business.
Explanation: Congress is a legislative group in the United States. They are the lawmaking branch of the United States government. When Congress gets together to make a legislative/law binding decision, they are in a session to conduct their meeting.
The correct answer is around 5% of the adult men population.