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.

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
B

In the morning, students observed puddles of water all over the playground. What would best explain why the playground was dry in the afternoon?  
 (A) Animals drank the water. (B) The wind stopped blowing. (C) Someone dried the puddles. (D) The water evaporated during the day.
D

Which gas makes up the greatest percentage of Earth's atmosphere?  
 (A) argon (B) nitrogen (C) nitrous oxide (D) carbon dioxide

B