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

  Options: 
 A. combustion.
 B. fixed proportions.
 C. conservation of mass.
 D. conservation of energy.
Answer: C