Question

Which of these discoveries is generally attributed to newton

A).The force of gravity acts between any two objects
B). The earth is round
C). Planets Move In circles
D). The orbit of mars is an ellipse

Answer 1

A. is the answer to the question 

Answer 2

Most people know that Newton said "A).".

Most people DON't know that Newton showed that
IF "A)." is true, then "D)." must also be true. Of all the planets.