1. which ancient astronomer developed a geocentric model of the universe explaining the observable motions of the planets?

a. aristotle
b. ptolemy
c. copernicus
d. newton

2. aristotle concluded that earth was round because

a. it always casts a curved shadow during a lunar eclipse
b. he sailed around the world
c. he calculated earth’s circumference
d. it exhibited retrograde motion

3. the first early astronomer to propose a sun-centered solar system was

a. galileo
b. newton
c. copernicus
d. brahe