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.
--------
Question: Some kinds of fish live most of their lives in salt water but lay their eggs in freshwater. Their ability to survive in different environments is an example of  
 (A) adaptation (B) developmental stages (C) a habit (D) selective breeding

Answer: A


Question: In the late 1700s, Antoine Lavoisier performed a series of experiments to find out what happened when a substance burned. In each experiment, he observed that the weight of a container and its contents was the same at the end of the experiment as it had been in the beginning. These observations led him to propose the law of  
 (A) combustion. (B) fixed proportions. (C) conservation of mass. (D) conservation of energy.

Answer: C


Question: From simplest to most complicated, how are multicellular organisms organized?  
 (A) organ system, organ, cell, tissue (B) organ, tissue, cell, organ system (C) tissue, cell, organ system, organ (D) cell, tissue, organ, organ system

Answer:
D