When they are all close, they are called clusters
The answer is true it can be traced to one particular reason.
The continental crust is made up of rocks that consist primarily of silica and alumina called the "sial". The next layer of the Earth is called the mantle.
The number 1 on the map identifies the Atlas Mountains. It is the mountainous region just south of the Mediterranean in Northwest Africa.
The Atlas mountains pass through the northern cost of West Africa, including Tunisia, Algeria, and Morocco. This impressive mountain range provided both advantages and challenges to civilizations in the region, and is host to a number of unique species.
