What measures distance north or south of the equator?

The correct choice is Parallels, which are lines that run east to west and are used to measure distances north or south of the equator. Each parallel is designated by its degree of latitude, starting from 0 degrees at the equator and extending to 90 degrees at the poles (both North and South).

Parallels help in defining geographical locations on the Earth's surface, as they provide a systematic way to denote how far a location is from the equator. Since the equator itself is defined as 0 degrees latitude, any location's latitude specifies its distance in degrees from this reference line.

In contrast, longitude measures distances east or west of the Prime Meridian and is not relevant for measuring north-south distances. Meridians, which are the lines of longitude, also serve a different purpose, focusing on east-west orientation rather than north-south positioning. Therefore, understanding the role of parallels is crucial for grasping how geographical coordinates work in terms of measuring areas on the Earth's surface related to latitude.