You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Q: Scientists have been able to insert genes from a spider into the genome of a domestic goat. When the goat matures, it produces milk that contains a protein found in spider webs. This protein can then be extracted and used to make strong but lightweight materials for bulletproof vests, automobiles, and aircraft. The change does not cause the goat any pain, but some people think that it is not right to add genes from the genome of one animal to another. Which word best describes this concern?  
 (A) economic (B) biological (C) ethical (D) practical

A: C
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Q: A student observed a rock made up of many small particles of sand arranged in light-colored layers and dark-colored layers. Which of the following statements describes how this type of rock most likely formed?  
 (A) Clay was crushed and frozen under a glacier. (B) Lava from a volcano cooled quickly in water. (C) River sediments were slowly compacted and cemented together. (D) Mineral deposits hardened into solid rock in underground caves.

A: C
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Q: A farmer thinks that the vegetables on her farm are not getting enough water. Her son suggests that they use water from the nearby ocean to water the vegetables. Is this a good idea?  
 (A) Yes, because there is plenty of ocean water. (B) Yes, because ocean water has many natural fertilizers. (C) No, because ocean water is too salty for plants grown on land. (D) No, because ocean water is much more polluted than rainwater.

A:
C
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