Final answer:
The length of an Earth year is based on Earth's revolution of approximately 1 degree/day, which takes about 365.2422 solar days to complete.
Step-by-step explanation:
The length of an Earth year is based on Earth's revolution of approximately 1 degree/day.
The Earth revolves around the Sun in an elliptical orbit. It takes approximately 365.2422 solar days for the Earth to complete one revolution around the Sun, which is known as a tropical year. This is the basis for our calendar year.
During this revolution, the Earth moves approximately 1 degree along its orbit each day, resulting in the change of seasons and the length of a year.