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.

The most significant human-induced impact on Earth's atmosphere comes from the use of which energy resource?  
 (A) flowing water (B) fossil fuels (C) sunlight (D) winds
B

In order to maintain good health, humans should  
 (A) eat foods high in fat (B) exercise regularly (C) drink alcohol often (D) smoke tobacco occasionally
B

What is the smallest particle of an element that still exhibits all the properties of that element?  
 (A) an electron (B) an atom (C) a molecule (D) a proton

B