Evolutionary history of plants seed model is shared by basically all gymnosperms (literally: "naked seeds"), most of which encase their seeds in a woody cone or fleshy aril (the yew, for example), but none of which fully enclose their seeds. The angiosperms ("vessel seeds") are the only group to fully enclose the seed, in a carpel. Fully enclosed seeds opened up a new pathway for plants to follow: that of seed dormancy. The embryo, completely isolated from the external atmosphere and hence protected from desiccation, could survive some years of drought before germinating. Gymnosperm seeds from the Late Carboniferous have been found to contain
Sub-provincial division Sub-provincial division A sub-provincial division () (or deputy-provincial divisions) in the People's Republic of China is like a prefecture-level city that is governed by a province, but is administered independently in regard to economy and law. Sub-provincial divisions, similar to prefectural-level divisions, an administrative unit comprising, typically, a main central urban area, and its much larger surrounding rural area containing many smaller cities, towns and villages. The mayor or chairman of a sub-provincial division is equal in status to a vice-governor of a province. Its status is below that of municipalities, which are independent and equivalent to provinces, but above