The first paper was made from the bark of the mulberry tree.

Alligators still exist in some of the dank 潮湿 swamps and bayous小海湾 of Alabama's coastal regions.

Formerly , in the United States, many nurses worked as private duty nurses rather than in hospitals.

Blue－green algae grow abundantly in salt marshes.

Eyespots, the most rudimentary eyes, are found in protozoan原生动物 flagellates 鞭毛虫 , flatworms 扁形虫 , and segmented worms片段 蠕虫 .