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]: Which of the following was most likely the cause of the extinction of 60-100 species of native birds in Hawaii since the arrival of colonists?  
 (A) habitat destruction (B) volcanic eruptions (C) increased salinity (D) tidal waves
[A]: A


[Q]: Which of the following is the best example of potential energy?  
 (A) a fallen rock (B) a burning match (C) a liter of gasoline (D) a red-hot piece of iron
[A]: C


[Q]: All atoms of an element have in their nuclei the same number of  
 (A) electrons. (B) isotopes. (C) molecules. (D) protons.
[A]:
D