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.

Example Input: Question: How long does it take the moon to circle the Earth? (A) 1 year (B) 1 week (C) 1 month (D) 4 months?
Example Output: moon, circle, Earth?

Example Input: Question: What trait might a tiger inherit from its parents? (A) Choice of mate (B) Hunting skills (C) Personality traits (D) Fur color?
Example Output: trait, tiger, inherit

Example Input: Question: Felicia noticed how air temperatures were cooler and there were fewer hours of daylight during some of the seasons. Which of the following contributes to these seasonal changes? (A) Earth rotates on its axis. (B) Earth revolves around the Sun. (C) The Sun has less energy in winter. (D) The Sun moves further from Earth in winter.?
Example Output:
air, temperatures, cooler, fewer, hours, daylight, contributes, seasonal, changes?