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: ___ are remains of the past life on Earth.  (A) Continents (B) Plates (C) Fossils (D) Pumic.
answer:
C.


question:
Question: The *** of a *** *** are to *** the *** and  (A) make food (B) produce fruit (C) take in water and nutrients (D) aid in germination.
answer:
E.


question:
Question: *** *** *** *** *** result *** *** decrease *** *** polar bear population *** *** arctic?  (A) An increase in the amount of grass (B) An increase in the fish population (C) A decrease in the fish population (D) A decrease in the human populatio.
answer:

E.