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.

Question: From which part of the plant does a bee get food? (A) flower (B) seed (C) stem (D) root?
part, plant, bee, food?

Question: What is the approximate length of time it takes the Moon to complete one lunar cycle? (A) 14 days (B) 29 days (C) 180 days (D) 365 days?
length, time, complete, one, lunar, cycle?

Question: Which of the following best describes the purpose of the chromosomes in the nucleus of a cell? (A) to store the genetic instructions needed to specify traits (B) to release energy by breaking down food molecules (C) to transport nutrients into and out of the cell (D) to protect the cells from microorganisms?

purpose, chromosomes, nucleus, cell?