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 of the following is the main role of flowers found on most flowering plants?  
 (A) to take in air (B) to produce seeds (C) to absorb nutrients (D) to protect the stem

Answer: B


Question: Which of the following properties best describes a material's ability to resist scratching?  
 (A) weight (B) flexibility (C) length (D) hardness

Answer: D


Question: Why do we see different stars in the sky at different times of the year?  
 (A) The stars are revolving around the Sun. (B) The Moon is revolving around Earth. (C) Earth is revolving around the Sun. (D) The stars are revolving around Earth.

Answer:
C