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.

Ex Input:
Question: The Moon orbits the Earth ___. (A) every 27.3 days (B) every 365.25 days (C) four times a year (D) every day?

Ex Output:
Moon, orbits, Earth


Ex Input:
Question: Which of the following systems breaks food into nutrients that can be used by the body? (A) circulatory. (B) digestive. (C) respiratory. (D) reproductive.?

Ex Output:
systems, breaks, food, nutrients, body?


Ex Input:
Question: Nancy plants the same flowers in her garden the same day as her neighbor does. After two weeks, however, she notices that her neighbor's flowers have made more blooms. The neighbor told Nancy that the secret was to put ground-up eggshells in the soil. Based on the given scenario, which of the following experiments best determine if grinding eggshells into Nancy's soil would make her flowers bloom more? (A) Plant identical flowers in two pots, one containing Nancy's soil and one containing her neighbor's soil (B) Transplant the neighbor's flowers to Nancy's garden (C) Plant identical plants in two pots of Nancy's soil, one containing ground-up eggshells in it (D) Transplant her flowers to the neighbor's garden?

Ex Output:

Nancy, plants, flowers, day, neighbor's, flowers, blooms., secret, ground-up, eggshells, experiments, determine, grinding, eggshells, make, flowers, bloom