The allowed shapes for the orbits of objects responding only to ...

[deesands]

The allowed shapes for the orbits of objects responding only to the force of gravity are
 
  A) ellipses, parabolas, and hyperbolas.
  B) ellipses only.
  C) ellipses, spirals, and parabolas.
  D) circles and ellipses.

Question 2

In the heliocentric (Sun-centered) model, apparent retrograde motion is due to
 
  A) relative motion between the Earth and another planet in its orbit
  B) the Earth reversing the direction of its orbit about the Sun
  C) a planet moving in a small circle, the center of which moves in a larger circle about the Earth
  D) a planet reversing the direction of its orbit about the Sun

[Jane]

Answer to Question 1

A

Answer to Question 2

A