The regions of lowest elevation in northern sub-saharan africa (i. e., between 10 and 20 degrees north latitude) tend to be

The regions of lowest elevation in northern sub-Saharan Africa (i.e., between 10 and 20 degrees north latitude) tend to be in the west.

Sub-Saharan Africa has a wide variety of climate zones, in this particular area (Nigeria/Congo) the climate is hot and humid in the lower elevation parts, this particular zone is in the western part of Africa, lying close to the equator.

Exposed great deposits of coal and iron ore