TASK DEFINITION: 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.
PROBLEM: Question: A mountain range has hills around its edges. How are the mountains and hills alike? (A) Both have grass at the top. (B) Both are at least 1000 meters tall. (C) Both have liquid rock at their centers. (D) Both are taller than the land around them.?

SOLUTION: mountains, hills, alike?

PROBLEM: Question: In 24 hours, the Earth completes ___. (A) one rotation on its axis (B) one rotation around the Sun (C) one orbit around Mars (D) one revolution around the Moon?

SOLUTION: 24, Earth, completes

PROBLEM: Question: Habitat destruction is one of the key factors in the endangerment and extinction of organisms. Which of the following is not a cause of habitat destruction? (A) Human overpopulation (B) Drought (C) Deforestation (D) Conservation?

SOLUTION:
cause, habitat, destruction?