Question

Why is it necessary to add a day to the calendar every four years?

A. The rotation of the Earth is actually 24 hours and 6 seconds.
B. The revolution of the Earth is actually 365.25 days not 365 days.
C. The Earth's orbit is elliptical and not circular.
D. The Earth's axis is tilted and slows its rotation.

Answer 1

B. The revolution of the Earth is actually 365.25 days not 365 days.

Answer 2

B. .25 x 4 equals one. Which is that one day we add.