What is a half of the world called?

Hemisphere

Explanation:

Hi, a half of the world is called Hemisphere.

The divisions can be latitudinal or longitudinal.

The Equator, or line of 0 degrees latitude, divides the Earth into the Northern and Southern hemispheres.  

The prime meridian, or 0 degrees longitude, divides the Earth into Eastern and Western hemispheres.  

Feel free to ask for more if needed or if you did not understand something.

answer; i believe the correct answer is (a) nigeria is the largest african crude (oil) supplier; /// so revenue from petroleum;