Question 15

0° longitude for east-west measurement

The prime meridian is accurately defined as 0° longitude, serving as the reference line for measuring longitude in an east-west direction. It plays a critical role in global navigation and timekeeping.

A) 66.5°N latitude

This option is incorrect because 66.5°N latitude refers to the Arctic Circle, which is not related to the concept of the prime meridian. The prime meridian is strictly a longitudinal reference, not a latitude.

B) 180° longitude

While 180° longitude is a significant meridian, it is not the prime meridian. Instead, it is the opposite meridian to the prime meridian, marking the boundary of the eastern and western hemispheres.

C) 0° latitude dividing hemispheres

This choice is incorrect as 0° latitude refers to the equator, which divides the Earth into the Northern and Southern Hemispheres. The prime meridian, however, pertains to longitude, not latitude.

D) 0° longitude for east-west measurement

This option is correct as it identifies the prime meridian as the line of 0° longitude, which is essential for determining east-west positions on the globe. This definition is fundamental to understanding global geography.

Conclusion

The prime meridian is definitively described by option D, as it accurately represents the reference line for longitudinal measurement at 0° longitude. All other options misrepresent geographic concepts either by referencing latitude or incorrect longitudes, thus failing to define the prime meridian appropriately.