The California region boasts a wide variety of climates and geographical features, rivaling any other area of comparable dimensions. Nearly all but the eastern-edge California Native Americans lived where environmental conditions were favorable, making food relatively accessible. Along the Pacific Coast, they hunted fish and sea mammals by boat. Included were such California tribes as the Chumash, Yurok and Pomo. The Maidu and Pomo principally ate acorns, which have a higher calorie rating than wheat. They pounded the hard nuts with stones and washed out the bitter taste with water.
The Pomo crafted what were arguably the finest baskets in all of indigenous America. They made baskets as small as a thimble and as big as a yard in width. They made watertight baskets for cooking acorn mush and seed gruel, as well as for carrying and storing food. They wove especially beautiful baskets for presents and as offerings to forebears. Some were bedecked with colorful bird feathers and shells. Their skill also was applied to trays, boats, headgear and baby carriers, such as a wickerwork cradleboard in which an infant spent his first year. Their mothers wore hats that resembled bowl-shape baskets.
The California natives lived in communities numbering up to 2,000 with dwellings arrayed in groups. A house consisted of a round frame covered with grass. There was a skylight in the roof and the beds were made on skin-covered frames—each with a partition for privacy. In the center of the floor, they made a cook fire for seeds, nuts, fish and other foods. More than 100 languages flourished in California before European contact; most are gone today.
From the passage we know that their houses were查看材料
A.round and strong
B.very dark
C.made of only grass
D.built in groups