Prime meridian is defined as which of the following?

• A. The Upper Branch of the Meridian That Passes Through Greenwich, England
• B. The Lower Branch of the Meridian That Passes Through Greenwich
• C. The Meridian at 180 Degrees Longitude
• D. The Line of Longitude That Coincides With the Equator

Answer: (A)

Longitudes are measured from a starting reference called the prime meridian, the line at 0 degrees longitude that runs from the North Pole to the South Pole and passes through Greenwich, England. This line serves as the origin for measuring east and west longitudes. The description that identifies the Greenwich meridian as the upper branch of the meridian passing through Greenwich aligns with that idea, since it points to the Greenwich line as the zero-longitude reference. The other options point to the anti-meridian at 180 degrees (not the prime), the equator (a latitude line, not longitude), or a lower branch of the Greenwich meridian, which isn’t how the prime meridian is defined. In short, the prime meridian is the Greenwich line at 0° longitude.