Answer:
A. Geocentric: This model is Earth Centered
. Retrograde motion is explained by epicycles
.
B. Heliocentric: This model is Sun centered. Retrograde motion is explained by the orbital speeds of planets
C. Both geocentric and heliocentric: Epicycles and deferents help explain planetary motion
. Planets move in circular orbits and with uniform motion
. The brightness of a planet increases when the planet is closest to Earth.
Explanation:
The principle of the Ptolemy's geocentric model was developed on the assumption that the center of the universe is the Earth. On the other hand, the principle of the Copernicus' heliocentric model was based on the assumption that the center of the universe is the sun. However, both models have a common ideology on uniform circular motion and epicycles.
The answer is mass. I have to comment more than 20 characters.
Oxygen....................
D
Because the rest of the answers are illogical
Yes that's correct. Also zeros in between non-zero numbers are significant figures
