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 Q]: Question: A student made observations of four rock samples. Which of these observations most likely describes a sedimentary rock? (A) Sample 1 has bands of light and dark crystals. (B) Sample 2 has pink, gray, and white crystals grown together. (C) Sample 3 is made up of one huge, pale pink crystal. (D) Sample 4 is made up of layers of sand grains cemented together.?
[EX A]: describes, sedimentary, rock?

[EX Q]: Question: Which of the following types of energy is lightning? (A) Solar (B) Heat (C) Nuclear (D) Electrical?
[EX A]: types, energy, lightning?

[EX Q]: Question: Some animals survive better when they live and interact with other animals. Which of the following is not an example of this interrelationship? (A) A small bird cleans food from a crocodile's teeth. (B) A zebra grazes in a herd. (C) A bird sits on its eggs in a nest. (D) A wolf hunts in a pack.?
[EX A]:
animals, survive, interact, example, interrelationship?