Make a comprehension about flags and make questions

Flags are symbols of a nation, state, or organization. They are usually rectangular in shape and feature a design or pattern that is unique to the country or organization. Flags are often flown from buildings, ships, and other structures to show allegiance or to represent a particular group.

Questions:

1. What is the purpose of a flag?
2. What shape are most flags?
3. Where are flags typically flown?
4. What does flying a flag signify?