instruction:
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.
question:
Which organ is the site of gas exchange between the body and the environment?  
 (A) spleen (B) liver (C) lungs (D) pancreas
answer:
C


question:
A student is dropping objects of various sizes and shapes and recording the time it takes for each object to hit the ground. Which question is the student most likely trying to answer?  
 (A) What force slows some objects down? (B) What force pulls objects to the ground? (C) Do some objects fall more quickly than others? (D) Do objects break or bounce when hitting the ground?
answer:
C


question:
A student notices a paw print while walking in a park. The paw print could be considered a fossil if the print was in ___.  
 (A) rock (B) topsoil (C) thick mud (D) loose sand
answer:

A