Question

How did Copernicus and Galileo build on the work of scientists in the Middle Ages?

Answer 1

they took theories that were applied years before and worked to make them better, to make them more true you could say

Answer 2

Copernicus started to doubt ancient Egypt astronomer called Ptolemy, his system did not answer many questions such as the movements of planets.

Because of his many doubts, he developed the heliocentric theory - in which the sun was in the center of the solar system - and published it.

After Copernicus published his theory, Galileo used the telescope and proved Copernicus theory, by noticing that not all moving bodies circled the earth.