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: The snowshoe hare sheds its fur twice a year. In the summer, the fur of the hare is brown. In the winter, the fur is white. Which of these statements best explains the advantage of shedding fur? (A) Shedding fur keeps the hare clean. (B) Shedding fur helps the hare move quickly. (C) Shedding fur keeps the hare's home warm. (D) Shedding fur helps the hare blend into its habitat.?

Output: snowshoe, hare, explains, advantage, shedding, fur?


Input: Consider Input: Question: A simple electromagnet can be made by wrapping metal wire around a nail, and attaching the ends of the wire to an electrical source. When the electrical source is turned on, the nail will (A) repel substances that normally respond to magnets. (B) reverse the flow of the electric current. (C) complete the circuit and cause the light bulb to light. (D) attract substances that respond to magnets.?

Output: electromagnet, wrapping, wire, electrical, source., nail


Input: Consider Input: Question: One way that students can help conserve natural resources at school is by (A) recycling aluminum cans. (B) emptying waste baskets. (C) wearing warmer clothes. (D) eating all of their lunch.?


Output: students, help, conserve, natural, resources