It is marked by 90° South latitude.
Explanation
The Earth's geographic coordinate system utilizes latitude to specify the north-south position of a point on the Earth's surface. The poles represent the two points where the Earth's axis of rotation intersects its surface. Latitude is measured in degrees ranging from 0° at the Equator to 90° at the poles.
Option Analysis
- It is marked by 90° North latitude. is incorrect: The latitude 90° North corresponds to the North Pole, which is located in the middle of the Arctic Ocean.
- It is marked by 90° South latitude. is correct: The South Pole is the southernmost point on the surface of the Earth and is defined by the latitude 90° South. It is located on the continent of Antarctica.
- It is located within the Torrid Zone. is incorrect: The Torrid Zone is the region located between the Tropic of Cancer (23.5° N) and the Tropic of Capricorn (23.5° S). The South Pole is located in the Southern Frigid Zone, which extends from the Antarctic Circle (66.5° S) to the South Pole.
- It serves as the reference point for the Prime Meridian. is incorrect: The reference point for the Prime Meridian (0° longitude) is the Royal Observatory in Greenwich, London. While the Prime Meridian terminates at the South Pole (as do all meridians), the pole itself is not the reference point defining the meridian system.
Key Takeaway: The South Pole is geographically defined as 90° South latitude and is the center of the Southern Frigid Zone.