Well it would be European explore such as people from Spain, France, Britain and places like that. There was also Christopher Columbus who was one of the reason for the native Americans being discovered and dying. However there was also Leif Eriksson Who was a Norse explorer that was believed to have led the first European expedition to North America 500 years before Christophers birth.
As I am thinking you mean "Producers" when you say "Sellers" I am going to go with, Yes. You are correct it is Supply. (Also the other one is called Demand not price)
