Question 51

The prime meridian is the line of longitude at 0 used to measure distance east and west.

The prime meridian serves as the reference point for measuring longitude around the globe, establishing the starting point for both eastern and western hemispheres.

A) The line of latitude at roughly 66.5N that marks the beginning of the Arctic region

This option incorrectly describes a line of latitude rather than longitude. The Arctic Circle is indeed at approximately 66.5 degrees north, but it does not pertain to the prime meridian, which is a line of longitude.

B) The line of longitude at 180 that defines the boundary between one day and the next

While the line at 180 degrees longitude does relate to the International Date Line and the concept of time zones, it is not the prime meridian. The prime meridian is specifically located at 0 degrees longitude.

C) The line of latitude at 0 that divides Earth into northern and southern hemispheres

This statement refers to the equator, which is the line of latitude at 0 degrees. The prime meridian, in contrast, is a line of longitude, thus making this option incorrect.

D) The line of longitude at 0 used to measure distance east and west

This statement accurately defines the prime meridian. It establishes the starting point for measuring longitude and is crucial in geographical coordinate systems.

Conclusion

The prime meridian is definitively described by option D as it is the line of longitude at 0 degrees, serving as the foundational reference for measuring distances east and west. All other options fail because they either refer to lines of latitude or incorrectly misidentify the prime meridian.