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: Where does prime rib come from on the cow?

Answer: cut of beef from the primal rib


Question: Who has to push the rock up the hill?

Answer: Sisyphus


Question: Rough endoplasmic reticulum is the site of synthesis of?

Answer:
certain lipids and cholesterol