Answer:
The primary reason the US advocated the Open Door Policy was to protect and broaden US trade with China. This policy was put into effect in the early 20th century after the Boxer Rebellion in China. It hastened the end of the last dynasty in Chinese history.
In an experiment, you used a solvent to extract fat from hamburger meat. When you are finished in the experiment, then you should put the solvent and the fat into waste containers that are specific for the solvent used in the experiment. You cannot just throw them into the sink as it may pollute and cause unwanted effect on bodies of water. Also, you cannot throw it together with other wastes as you do not know the reaction that would happen with it with the other wastes.
The answer is A. They moved to the cities for the jobs and employment.
