Which one is secondary source and which one is primary source

What best describes the transportation within cities in the early 1800s

What are the strengths of the byzantine empire?

What was the biggest difference between government in ancient athens and in ancient rome? rome was a direct democracy, and athens was not. athens allowed all citizens to vote, while rome was a republic. athens allowed women and slaves to vote, but rome did not. rome had a bicameral assembly, and athens did not.