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: Which unit of measurement describes an object's length? (A) meter (B) kilogram (C) liter (D) degree?
unit, measurement, length?

Question: From Earth, we see the sun in the day sky and other stars in the night sky. Nighttime stars look like tiny points of light. Which statement explains why nighttime stars appear so much smaller than the sun? (A) The stars are much smaller. (B) The sky is much darker at night. (C) The stars are much farther away. (D) The moon blocks out most starlight.?
explains, nighttime, stars, appear, smaller, sun?

Question: Minerals have different properties that help scientists identify them. Which of the following is NOT a property used to identify minerals? (A) luster (B) hardness (C) size (D) color?

Minerals, properties, identify, used, identify, minerals?

