Question

what is the main reason the length of a year on earth is approximately 365 days? the phases of the moon the revolution of earth around the sun earths rotation on its axis the tilt of earths axis

Explanation:

A year is defined by Earth's orbital period around the Sun. The Moon's phases relate to lunar cycles, Earth's rotation gives day - night cycles, and the axial tilt causes seasons.

Answer:

The revolution of Earth around the sun