Volcanic deposition and river erosion have both shaped parts of Idaho over geological time. is the correct choice. Basalt forms from cooled lava, while river erosion can cut deep gorges such as Hells Canyon.

Idaho Territory was created in 1863; the territorial capital moved from Lewiston to Boise in 1864; Idaho became the 43rd state in 1890. Territorial, state, county, federal, and tribal governments are distinct institutions with different legal responsibilities.