Answer:
1. Knapping
2. Different technique implies different people
3. The desert areas of nowadays Arabia were once green areas.
4. Food shortage and/or climate changes
5. See explination nr. 2
Step-by-step explanation:
1. 'Knapping' is the process of knocking of flakes of a stone.
2. Theories of archeologists are very often based on (logic) assumptions. When there is a certain stone tool technique in one and another in a different place, they assume they must be from different people.
3. The migration by land was made possible through climate changes that ranges from an ice corridor that once connected Alaska with Iberia, to more hospitable environments of lakes and rivers with an abundance of plants and animals in what is now the Arabic desert.
4. The same climate change (warming up) that caused more hospitable environments - deeply connected with foodsupply - along the mediterranean sea might have caused a dryer and less hospitable environment in East Africa.
5 is answered the same way as question nr. 2 but now with the same tools, and thus the same people who must have traveled.
P.S. Archeologists agree on the emigration of early humans from Africa to other continents; they donĀ“t agree on When. Genetic study claims that it was about 60.000 years ago, but the findings at Jebel Faya and other places suggest that this might have happened (much) earlier.