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: If water gets into the crack of a rock and then freezes, the rock will MOST likely (A) break apart (B) be able to float (C) become larger (D) change colors?

Output: water, crack, rock


Input: Consider Input: Question: Which of the following equipment protects your eyes? (A) Graduated cylinder (B) Magnifying glass (C) Microscope (D) Goggles?

Output: protects, eyes?


Input: Consider Input: Question: Wind can cause erosion that changes the surface of the Earth. Wind erosion can have negative effects on the environment by removing soil and polluting the air during dust storms. Which of the following land forms are created by wind erosion? (A) arches and faults (B) sand dunes and arches (C) meanders and moraines (D) moraines and sand dunes?


Output: land, forms, created, wind, erosion?