The reason leap years have an extra day is to account for the fact that the
A) Earth's rotation period is slowly increasing because of tidal effects.
B) year is not exactly equal to an integral number of days.
C) day is not exactly 24 hours because of Earth's periodically varying rotation period.
D) length of the year varies with a period of four years because of precession.

Question

Quizplus · Accepted Answer

The reason leap years have an extra day is because a year (the time it takes for Earth to orbit the Sun) is not exactly 365 days but approximately 365.25 days. Adding an extra day every four years compensates for this discrepancy, keeping the calendar year synchronized with the astronomical year.

The Reason Leap Years Have an Extra Day Is to Account