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: A biological community is made up of all the  
 (A) populations living in an area (B) natural resources present in an area (C) members of a species on Earth (D) environments on Earth

A: A
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Q: Which of these will most likely result from small meteoroids entering the atmosphere of Earth?  
 (A) a decrease in air temperature (B) the appearance of shooting stars (C) an decrease in atmospheric ozone (D) the appearance of the Northern Lights

A: B
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Q: When Javier exercises, his muscle cells need more oxygen. Which would help Javier's muscle cells receive more oxygen?  
 (A) decreasing his respiration rate (B) increasing his perspiration rate (C) increasing the rate his heart beats (D) decreasing the rate his blood flow

A:
C
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