Title: Flowering plant.
Question: What system did Arthur Cronquist put forth in 1968, but not publish in full form until 1981?

Title: Capital punishment in the United States.
Question: How many people were killed in the largest mass execution in US history?

Title: Chicago Cubs.
Question: When did Babe Ruth retire?

Title: Roman Republic.
Question:
How many of the Roman military were involved in the Battle of Allia River?