In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

What body of water do the tigris and euphrates rivers empty into?
Shatt al-Arab

Who is the founder of babylon as recorded in the bible?
Nimrod

What type of garbage is thrown in green bins?

biodegradable waste or compostable materials