Answer:
Stephen Hawking
Explanation:
First man who came to mind, he has made many discoveries about black holes and the Universe and has a famous book.
The event that marked the end of the Roman Republic is often attributed to the defeat of Marc Antony in 31 BC at the Battle of Actium which ended the period of civil war.
Legislative branch I believe it is
A bill becomes law if signed by the President or if not signed within 10 days and Congress is in session. If Congress adjourns before the 10 days and the President has not signed the bill then it does not become law ("Pocket Veto.")