In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to write a question that clarifies the given question in such a way that the generated question has one unique answer.

Where does lymph fluid drain in order to go back into the cardiovascular system?
Which veins does lymph fluid drain in order to go back into the cardiovascular system?

Who achieved a victory at the battle of marathon?
What country achieved a victory at the battle of marathon?

When did the first free settlers arrived in australia?

Upon what event did the first free settlers arrive in Australia?