Which lines are used to define latitude and longitude on Earth?

• A. Arctic Circle and Antarctic Circle
• B. Tropic of Cancer and Tropic of Capricorn
• C. Equator and Prime Meridian
• D. International Date Line and Equator

Answer: (C)

Latitude is measured north or south from the Equator, which is the zero line for latitude. Longitude is measured east or west from the Prime Meridian, the zero line for longitude that runs from the North Pole to the South Pole through Greenwich. Together, these two reference lines define coordinates on Earth. Other lines like the Arctic/Antarctic Circles or Tropics are specific parallels, not the reference system for measuring latitude and longitude, and the International Date Line pertains to calendar dates rather than the coordinate framework. So the lines used to define latitude and longitude are the Equator and the Prime Meridian.