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.
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Question: A DNA strand contains codons, which consist of a sequence of three nucleotides. Which best describes the importance of codons found in the sequence of DNA?  
 (A) They contain the code for messenger RNA. (B) They signal the start of mitotic cell division. (C) They ensure proper replication of the genetic code. (D) They are used to assemble amino acids for protein synthesis.

Answer: D


Question: Which animal is preparing for a seasonal change in the environment?  
 (A) a bat flying at night (B) a deer drinking water (C) an owl eating a mouse (D) a squirrel storing nuts

Answer: D


Question: When gasoline in a car engine is burned, only about 15 percent of the gasoline is converted into mechanical energy. This is because most of the energy in the gasoline is  
 (A) transformed into heat. (B) stored for use at a later time. (C) changed into chemical energy. (D) used to make the vehicle move.

Answer:
A