What line marks where each day begins and ends on Earth?

What line marks where each day begins and ends on Earth?

• A. Prime Meridian
• B. Equator
• C. International Date Line
• D. Tropic of Cancer

Answer: (C)

Date boundaries on Earth are defined by the International Date Line, the line where the calendar day changes. It sits roughly along the 180th meridian opposite the Prime Meridian, though it bends around landmasses to keep countries intact. Crossing this line from one side to the other shifts the date by one day, which is why it’s described as where each day begins and ends. The Prime Meridian marks 0 longitude and is a reference for time zones, the Equator is 0 latitude separating the northern and southern hemispheres, and the Tropic of Cancer is a northern latitude line. None of those determine the calendar date in the same way.

Date boundaries on Earth are defined by the International Date Line, the line where the calendar day changes. It sits roughly along the 180th meridian opposite the Prime Meridian, though it bends around landmasses to keep countries intact. Crossing this line from one side to the other shifts the date by one day, which is why it’s described as where each day begins and ends. The Prime Meridian marks 0 longitude and is a reference for time zones, the Equator is 0 latitude separating the northern and southern hemispheres, and the Tropic of Cancer is a northern latitude line. None of those determine the calendar date in the same way.