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: A student perfoms an *** by *** *** *** different amounts of *** for a ***. At the *** of the ***, she *** the *** mice. *** the *** is an *** of  (A) a measurement (B) a hypothesis (C) an explanation (D) background researc.
E.

Question: Which of the following enables an *** to get ***?  (A) Digestive System (B) Cirulatory System (C) Respiratory System (D) Nervous Syste.
E.

Question: A mother hen *** loudly when danger is near and her chicks quickly gather around her. Which *** helps the chicks receive this warning about danger from their mother?  (A) smell (B) taste (C) sight (D) sound.

D.