You are given a science question (easy-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: What is the primary function of white blood cells in humans?  
 (A) carry oxygen (B) fight disease (C) grow tissues (D) remove waste

A: B
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Q: Which of the following was most likely the cause of the extinction of 60-100 species of native birds in Hawaii since the arrival of colonists?  
 (A) habitat destruction (B) volcanic eruptions (C) increased salinity (D) tidal waves

A: A
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Q: Which of these materials on the walls of a room would work best to keep sound from making an echo?  
 (A) marble (B) carpet (C) wood (D) glass

A:
B
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