Despite temperatures of more than 5,000º f, earth's inner core is solid because of
a layer of ice just above it. the fact that earth rotates so quickly. a thickness of over 1,000 miles. great pressure from the layers around it.

Its 'great pressure from the layers around it

During the paleolithic, hominins grouped together in small societies such as bands, and subsisted by gathering  plants  and fishing, hunting or scavenging wild  animals. the paleolithic is characterized by the use of knapped stone tools, although at the time humans also used  wood  and bone tools.

Ithink or blue