Question

what is the prime meridian?

Explanation:

The prime meridian is an imaginary line (a meridian) at 0° longitude, passing through Greenwich, London, UK. It serves as the reference line for measuring longitude (east - west positions) on Earth's surface, dividing the Earth into the Eastern and Western Hemispheres.

Answer:

The prime meridian is the imaginary line of 0° longitude, passing through Greenwich, London, that is used as the reference for measuring longitude (east - west locations) on Earth, dividing the planet into the Eastern and Western Hemispheres.