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 part of an atom is involved in chemical reactions?  
 (A) nucleus and its particles (B) negatively-charged particles (C) neutrally-charged particles (D) positively-charged particles
[A]: B


[Q]: A meeting of scientists, called a symposium, occurs every year to share recent research about the atmosphere of Earth. This symposium mainly serves which purpose in science?  
 (A) to test research methods used by other scientists (B) to develop questions about space research (C) to discuss the meaning of new discoveries (D) to explain gas properties to the general public
[A]: C


[Q]: There are different types of desert. What do they all have in common?  
 (A) warm winters (B) long summers (C) low rainfall (D) low day and night temperatures
[A]:
C