The exchange that most affected the indigenous people was the one of diseases. Native Americans hadn't encounter the diseases the European brought before, so they hadn't develop immunity to them. This is the major reason of the large death of Native Americans, besides the war between them and the brutality of the Europeans.
The answer is C.
Speeding was involved in 35% percent of the fatal crashes that occurred in construction/maintenance zones. Speeding lessens the ability of the driver to safely steer on the highway curves and to prevent crashing on anything in the road.
