In this task, you need to answer basic science questions. For each question, several terms are intentionally masked with ***. This masking can cover very few or many of the question words. Clearly, if masked terms are important, the modified question will be impossible to answer. Please indicate the correct answer with one of the following responses: "A", "B", "C", "D" or "E". While "A"-"D" correspond to the answer options provided in the input, "E" represents "I don't know" for questions that do not provide enough information. Respond via "E" if the question is not answerable. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'.

Q: Question: A student found a *** while *** in the ***. By *** at the rock, she could *** the  (A) exact weight of the rock. (B) length of time the rock had been on the hiking path. (C) color and shape of the rock. (D) exact length of the rock.

A: E.
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Q: Question: When *** *** human *** *** *** reached *** adult stage?  (A) When cells no longer divide (B) When the human has begun to talk (C) When the human has begun to walk (D) When most growth has stoppe.

A: D.
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Q: Question: A student is given three identically sized blocks. Each block is made of a different material. What *** of the blocks should be examined to find out which block is made of ***?  (A) color (B) weight (C) texture (D) conductivit.

A:
E.
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