Answer:
1.As Earth continues its spin, we are moved to the side facing away from our Sun, and we have nighttime.
2.Sorry,I don't know the ans of 2.
3.Adding one extra day in the calendar every four years compensates for the fact that a period of 365 days is shorter than a tropical year by almost 6 hours.
4.Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays.