You are given an elementary science question along with a few answer options. List all the words from the question that are essential and sufficient for choosing the correct answer option. Keep in mind that essential words are necessary to understand the meaning of the given question. However, non-essential words provide little information needed to select the correct answer. You can think about it like this: If the question was in another language, knowing the meaning of which words were necessary and enough for you to understand the question and answer it?. If your answer consists of multiple spans of words from the question, separate those using a comma (", "). Do not generate any word that is not present in the question. Make sure that your response is contained in the given question and the words are in the same order as the question.
 Grammatical correctness is not important.

Input: Consider Input: Question: Which of these tells something about how an apple looks? (A) It is soft. (B) It is blue. (C) It is square. (D) It is smooth.?

Output: apple, looks?


Input: Consider Input: Question: Some animals, such as squirrels, may bury acorns. Which of the following is most likely to happen to the acorns after they have been buried? (A) The acorns will be carried away by the wind. (B) The acorns will attach to another organism. (C) The acorns will have a chance to sprout. (D) The acorns will turn into fossils.?

Output: bury, acorns., happen, buried?


Input: Consider Input: Question: Heating and cooling water change the state of matter of water. What happens when a block of ice is heated to 10° Celsius? (A) It melts to form liquid water. (B) It condenses to form liquid water. (C) It freezes to become heavier ice. (D) It evaporates to become a vapor (gas).?


Output: block, ice, heated, 10°, Celsius?