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: When a person speaks, the type of wave produced can be described as all these except  
 (A) transverse. (B) mechanical. (C) compression. (D) longitudinal.

A: A
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Q: Plants growing in a pond release a gas that fish need to survive. Which gas do the plants release that fish use?  
 (A) helium (B) hydrogen (C) nitrogen (D) oxygen

A: D
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Q: The endangered Florida manatee is a large, aquatic mammal that feeds on sea grasses in brackish water. Due to where they like to feed, manatees are vulnerable to injuries from boat propellers. If speed zones requiring boats to maintain a low speed are placed in areas where manatees are known to congregate, which will most likely occur?  
 (A) less water pollution in manatee habitats will occur (B) manatees will seek alternate food sources (C) new manatee predators will surface (D) manatee populations will increase

A:
D
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