Why does a year have 365 days?

Answer: Time for Earth to orbit the Sun

Earth rotates 365 times yearly — Wrong. Earth actually rotates about 366 times during one orbit of the Sun, not 365. We count 365 days because a 'day' is based on the Sun's position in the sky, which is affected by Earth's orbit as well as rotation.

Time for Earth to orbit the Sun ✓ — Correct! A year is defined by how long Earth takes to complete one full orbit around the Sun - approximately 365.25 days. This is determined by Earth's orbital distance (93 million miles) and speed (67,000 mph). We round to 365 days for convenience, adding a leap day every 4 years to account for the extra 0.25 days. This orbital period is a natural astronomical fact, not a human invention.

The Moon's cycle determines it — Wrong. The Moon's cycle (29.5 days) doesn't determine Earth's year. Some ancient calendars were lunar-based, but Earth's year is determined by its orbit around the Sun. The Moon's orbit around Earth and Earth's orbit around the Sun are independent cycles.