In the Paleolithic age, hunter-gatherers began to use stone tools and fire to hunt animals, warm themselves, they eat simple things like grass, fruit and berries. In addition, they were wearing thick clothes.
However, they didn't have a fixed place to live. Most of them spent the night in caves or even some open places together. They were gradually adapting to the surroundings.
Gradually, in the Neolithic age, on the basis of eating some vegetarians, hunter gatherers tried to make spears with stone tools in order to better capture large animals and obtain meat.
With the end of the ice age, the Earth's temperature gradually increased, more and more rivers and plants appeared. This temperature change illustrated the beginning of the Agricultural Revolution.
Due to the extinction of many animals by the end of ice age, they had to plant their own plants like wheat, and try to domesticate and raise some animals, such as sheep, pigs and so on.
Moreover, they chose resource-rich places, built huts made of wood and rock, and some farmlands, permanent settlements and villages began to form.