Final answer:
Climate played a crucial role in shaping the lifestyles and cultures of the Coastal and Plateau tribes. The mild climate of the Coastal region allowed for sedentary life with permanent villages, while the harsher climate of the Plateau led to a more mobile lifestyle with some level of settlement.
Step-by-step explanation:
The differences in climate significantly affected the lifestyles and cultures of the Coastal and Plateau tribes. For the Coastal tribes in the Northwest Coast, a mild climate and abundant natural resources, especially from the ocean, enabled them to be sedentary and form large, stable communities. On the other hand, the Plateau tribes lived in a less populated region with a harsher climate, prompting them to adapt a semi-nomadic lifestyle, moving to follow resources while also maintaining some permanent villages near rivers and streams.
Thus, option A is correct: A mild climate allowed the Coastal peoples to live in one place, while a harsh climate made the Plateau peoples move around, though it is essential to note that the resources available to the Plateau peoples allowed for some level of settlement.