Complex sentence: The Gwoza Hills, with heights of about 1300m above sea level provides scenery and is made up of the Mandara Mountains, which form a natural barrier between Nigeria and Cameroon, starting from Pulka.
Split into simpler sentences: The Gwoza Hills, with heights of about 1300m above sea level provides scenery and is made up of ranges of mountains known as the Mandara Mountains. These mountains form a natural barrier between Nigeria and Cameroon, starting from Pulka.