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: Carolina uses a microscope to view a soil sample taken from her backyard. Which part of the soil would she ONLY be able to see with a microscope?  
 (A) bacteria (B) grass (C) rainwater (D) rocks

A: A
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Q: At what time on a sunny day will the shadow of the school's flagpole be the shortest?  
 (A) sunrise (B) noon (C) mid-afternoon (D) sunset

A: B
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Q: Which organ is part of the respiratory system?  
 (A) stomach (B) lungs (C) spinal cord (D) large intestines

A:
B
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