Answer:
Europeans, maybe also Americans.
Explanation:
The Europeans are the most apparent. Britain and Germany were incredibly strong forces in China during and leading up to the Boxer Rebellion. America was also heavily involved. If I had to choose one, I would say Europe, but if not Europe and America were both heavily involved.
Native peoples of America had no immunity to the diseases that European explorers and colonists brought with them. Diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to American Indians. Europeans were used to these diseases, but Indian people had no resistance to them.
If your meaning 'Select all the apply', then it's B and D.
Smooth road bc the others might enforce some type of friction on the ball cause it to go slower
