TASK DEFINITION: You are given a science question (hard-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: Leucine is one of the amino acids your body needs but cannot make. Which of these happens so that the human body can obtain leucine?  
 (A) The body converts other amino acids to leucine. (B) The body stores carbohydrates containing leucine. (C) The body breaks down fatty acids to obtain leucine. (D) The body digests protein in food to obtain leucine.

SOLUTION: D

PROBLEM: What is the first step of the process in the formation of sedimentary rocks?  
 (A) erosion (B) deposition (C) compaction (D) cementation

SOLUTION: A

PROBLEM: The cellular membrane surrounds every human cell. The membrane protects the cell and transmits information about the cell's surroundings to organelles inside the cell. What organ system provides a similar function in the human body?  
 (A) endocrine system (B) skeletal system (C) integumentary system (D) lymphatic system

SOLUTION:
C