The challenges humans faced is the climate weather and temperature. Which means they had to learn to adapt and have survival skills. Because of these factors, they have the issues of finding a settlement and growing crops and domesticating the animals. Technically, the transition between the Paleolithic and Neolithic is the turning point for the nomads. Where people began to have a settlements, easier growing foods besides hunting and gathering, have their own domestic animals to help them do the fields and etc. Which domesticating an animal led to selective breeding.