Final answer:
a) Yellowstone, Hawaii
The two active intraplate zones in North America are Yellowstone, marked by geothermal activity and past volcanic eruptions, and Hawaii, characterized by ongoing volcanic activity forming the Hawaiian Islands.
Step-by-step explanation:
The two relatively active intraplate zones in North America (NA) are Yellowstone and Hawaii. The Yellowstone area is a known hotspot with a history of massive volcanic eruptions and is geologically active with geysers and hot springs, characteristic features of an active hotspot. The Hawaii hotspot is also famous for its active volcanic islands, such as the Big Island, where Kilauea and Mauna Loa volcanoes are located. These intraplate zones do not lie along plate boundaries but within the interiors of tectonic plates.
Yellowstone is beneath Yellowstone National Park and is responsible for the region's famed geothermal features, while the Hawaiian hotspot is beneath the Pacific Ocean, forming the Hawaiian Islands. Both are evidence of mantle plumes that extend from below the Earth's crust, creating volcanism at the surface.