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.

[EX Q]: In animal skin tissue, cell division is responsible for  
 (A) growth and repair (B) sexual reproduction (C) obtaining energy (D) production of sex cells
[EX A]: A

[EX Q]: Which of these is a structure that is present in all organisms?  
 (A) a tissue (B) a cell (C) a stomach (D) a brain
[EX A]: B

[EX Q]: Strontium, barium, and radium are grouped together on the Periodic Table of the Elements because they all have  
 (A) a bright silver and white coloring. (B) similar electron configurations. (C) strong radioactive properties. (D) few or no stable isotopes.
[EX A]:
B