Europeans carried a hidden enemy to the Indians: new diseases. 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.
The best option from the list would be "<span>a series of failed economic programs," since it was operating under a "command economy"--meaning that government had to "guess" supply and demand. </span>
<span>executive
legislative
federal
judicial</span>
