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.
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Question: Who played chip douglas on my three sons?

Answer: Stanley Livingston


Question: Journal of optics a pure and applied optics abbreviation?

Answer: J. Opt.


Question: What is the lining of the medullary cavity called?

Answer:
endosteum