instruction:
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'.
question:
Question: *** *** *** difference *** *** food chain *** *** food web?  (A) A food chain always ends with a primary consumer. (B) A food web is made up of many food chains. (C) A food web only shows one flow of energy through the ecosystem. (D) A food chain is made up of many food webs.
answer:
B.


question:
Question: Which is most like the way a *** supports a ***?  (A) the way water supports a boat crossing a river (B) the way a flagpole supports a flag in the schoolyard (C) the way bookends support books on a shelf (D) the way a belt supports pants on a person's wais.
answer:
E.


question:
Question: The systems of the human body work together. Which *** works with the *** *** by pulling on the bones to create ***?  (A) digestive (B) circulatory (C) muscular (D) nervou.
answer:

C.