TASK DEFINITION: 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.
PROBLEM: Which human organ system eliminates liquid and gaseous wastes from the body?  
 (A) circulatory (B) endocrine (C) excretory (D) reproductive

SOLUTION: C

PROBLEM: Earth is composed of layers of material with different properties. Which of the following is most likely to be in constant motion?  
 (A) core (B) mantle (C) oceanic crust (D) continental crust

SOLUTION: B

PROBLEM: Sodium bicarbonate (NaHCO_{3}) is commonly known as baking soda. Sodium bicarbonate is a white solid that can dissolve in water. Under the proper conditions, sodium bicarbonate can release carbon dioxide (CO_{2}) gas. Which of the following is not a physical property of sodium bicarbonate?  
 (A) It is white. (B) It is a solid. (C) It can dissolve in water. (D) It releases carbon dioxide.

SOLUTION:
D