It originates in the inner core of the Earth.
Hunter-gatherer societies are often nomadic. I believe.
the answer is a because if the model is based on experimental data it wont be good unless it has been tested.
Gene flow is the phenomenon of transfer of gene from one species/population to others. According to Natural Selection, more suitable (which fits best with the environment) gene/allele make the characteristic of that individual. So, it increases the ability to survive and reproduction
Hope this helps!
