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: A student has a ball of clay that sinks when placed in a pan of water. Which property should he change to make the clay float? (A) color (B) texture (C) mass (D) shape?
clay, sinks, water., property, change, float?

Question: Which statement best explains why the Sun and the Moon appear to be about the same size in the sky? (1) The Sun and the Moon have the same diameter. (2) The Moon is larger in diameter and farther from Earth than the Sun. (3) The Moon is smaller in diameter and is closer to Earth than the Sun. (4) The Sun and the Moon are the same distance from Earth.?
Sun, Moon, appear, size

Question: Which two activities are carried out by all species of living things? (A) make food and eliminate waste(B) hibernate and take in nutrients(C) grow and reproduce(D) migrate and seek shelter?

activities, living, things?