instruction:
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.
question:
Are radio waves electromagnetic waves or sound waves?
answer:
electromagnetic waves


question:
Who ordered the translation of the old testament into greek?
answer:
Ptolemy II Philadelphus


question:
Who sang those were the days my friend?
answer:

Mary Hopkin