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.

Input: Consider Input: Similar types of cells form tissues. What is the next level of complexity formed from the grouping of tissues?  
 (A) organs (B) organelles (C) organisms (D) organ systems

Output: A


Input: Consider Input: Which force produces energy as heat?  
 (A) pull (B) gravity (C) friction (D) magnetic

Output: C


Input: Consider Input: Which is an example of metamorphosis?  
 (A) A caterpillar changes into a butterfly. (B) An earthworm tunnels through the soil. (C) A lizard lays eggs in the sand. (D) A giraffe eats leaves from a tree.


Output: A