Which sentence should be added to maintain the flow of ideas? from Eclipses
Source: The National Park Service

Eclipses are profound events for those who witness them. For thousands of years, people have observed and interpreted these phenomena.
A lunar eclipse occurs when the Earth moves between the sun and the moon, blocking the sunlight that is normally reflected by the moon. A solar eclipse occurs when the moon is directly between the sun and the Earth, casting a shadow on the Earth.