Short answers, pulled from the story.
Some of the oldest Homo sapiens remains yet discovered were found at Jebel Irhoud in Morocco. They suggest that early Homo sapiens may have been present across the length of Africa roughly 100,000 years before the previously assumed date of around 200,000 years ago in East Africa.
The United Nations definition of North Africa includes Algeria, Egypt, Libya, Morocco, Tunisia, Western Sahara, and Sudan. The African Union uses a similar definition but excludes Sudan and includes Mauritania instead.
The early Muslim conquests reached North Africa by 640. By 700, most of the region had come under Muslim rule. A major wave of Arab migration, including the Banu Hilal and Banu Sulaym, followed in the eleventh century and heavily shifted the demographics of the Maghreb.
Rapid desertification of the Sahara occurred around 3500 BCE, largely due to a tilt in the Earth's orbit. Grazing during the preceding Neolithic period amplified the natural drying by spreading shrubs and open land across the terrain.
Arabs make up 92% to 97% of Libya's population and 98% of Tunisia's population. Berbers form a more significant minority in Algeria, at around 20%, and Morocco, at around 35%.
North Africa was a critical grain province that sustained Roman prosperity even during periods of barbarian pressure elsewhere. When Germanic Vandals seized the region in the early fifth century, Rome lost both the food supply and the revenue needed to rebuild its armies. Rome's last serious attempt to retake North Africa came in 468 AD and failed, a moment widely regarded as marking the terminal decline of the Western Roman Empire.