Question

How did further exploration prove that Christopher Columbus had not landed in Asia?

Answer 1

in the medieval times, everyone knew about the wealth, spices, vegetation and the appearance of people from asia. so, when columbus landed in america, he knew that he had not landed in asia and discovered some unknown land because of the amount of knowlegde available at that time. However, Amerigo Vespucci was the first person to doubt it and went for further exploration and hence the name America.

(follow if you find it useful)