What do parallels of latitude represent?

Parallels of latitude are important in understanding the Earth's geography and navigation. They are defined as lines that run parallel to the equator, which is considered the central line of latitude. As you move from the equator towards the poles, these lines form small circles that progressively decrease in diameter.

The correct option highlights that parallels of latitude originate at the equator and extend up to the poles, effectively creating a series of circles around the Earth. This concept is crucial for navigation because it helps determine geographical coordinates, aiding in the identification of locations and the calculation of distances. Each degree of latitude represents approximately 69 miles (111 kilometers) on the Earth's surface, which is essential for navigators to plot courses and understand their position.

The other options do not accurately describe parallels of latitude. Lines that run from the north pole to the south pole refer to lines of longitude, not latitude, while circles centered on the equator suggest the concept of latitude but do not emphasize the nature of parallels as small circles. Lastly, great circles relate to the largest circles that can be drawn around the Earth, often used in time zone demarcation, but they are fundamentally different from the concept of parallels of latitude.