A.
Why because google directly stated it when you typed in this question ✨
Florence
The Italian city was home to the greatest thinkers and artists of the Renaissance.Some of the artists were Michelangelo and Leonardo Da Vinci.<span>Florence
became Italy's leading cultural center during the Renaissance because
it was centrally located and had great wealth, and was home to many of the
great thinkers of tile period.</span>
Answer: Heliocentrism (the sun is the center of the solar system)
The prior belief was that the earth was the center of the solar system (geocentrism)
it's number d.
because Americans immunity system wasn't strong as for that of the Europeans
I hope it helps ;D