The crafting of items like shell beads by the Chumash and watertight baskets by other groups best demonstrates what aspect of California Indian life?

A complete reliance on agriculture

The skillful use of local natural resources

A single, unified government across the region

Extensive trade networks with European explorers

For what primary purpose did some California Indian groups use obsidian?

To create decorative beads for trade

To craft sharp tools for hunting and building

To weave watertight baskets and boats

To build the foundations of their homes