sentence: Earth rotates so each part of it is in light during the day and dark at night.
sentences_before: It has only one Moon. Every 365 days it revolves around the Sun which provides light.
sentences_after: The Moon revolves but the same side of it is always facing Earth. The lunar calendar is based on this.
concept_name: earth
headings: Wikipedia:Simple talk/tier sample Level 3 (harder level)