How do we have evidence of hunter gatherers and their lifeways

The reason why we have evidence of hunter-gatherers (h-g) and their lifeways are: Archeology and paleobiology
Through paleobiology, we managed to study several existing fossils, which became the evidence of hunter-gatherers' existence and through Archeology, we could know their lifestyle from the tools and buildings that they left.

The political system that has multiple political parties is most common in the parliamentary system. Some of the countries that use multiple political parties are Germany, Finland, Italy, South Africa, and Sweden.