What types of changes took place
during the 1920s that led to the use of
the term Roaring Twenties'?

The 1920s in the United States, called “roaring” because of the exuberant, freewheeling popular culture of the decade. The Roaring Twenties was a time when many people defied Prohibition, indulged in new styles of dancing and dressing, and rejected many traditional moral standards. (See flappers and Jazz Age.)

s the president shall be commander in chief of the army and navy of the united states, and of the militia of the several states, when called into the actual service of the united states; he may require the opinion, in writing, of the principal officer in each of the executive departments. sooo yeahhh

explanation:

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.