Answer:
A- to provide a reference system
Explanation:
The equator and prim meridian used on maps provides a reference system for determining location and navigating the earth.
An equator is the only line of latitude that is a great circle.
Prime meridian is a line of longitude that is 0°
When both are used, they can form the basis of a reference system to determine places on earth.
Using these lines, we can assign values of coordinates to the earth surface to facilitate location determination.
The equator and prime meridian are used on maps to provide a reference system.
