Which of the following is the reason for the leap years?
A) precession of Earth's axis
B) the tilt of Earth's axis
C) the combined effect of the rotation of Earth and its orbit about the Sun
D) Earth year being a non-integer number of Earth days
E) the non-circular orbit of Earth around the Sun
Question 2
For most of human history it was believed that the Earth was at the center of the universe. This idea is referred to as
A) heliocentric
B) egocentric
C) geocentric
D) stellocentric