<span>Before the emperors, Japan many clans, of which the Yamato clan was most powerful. The clan chief became the first emperor of Japan, and his descendants have ruled Japan until today.</span>
Karst is a topography formed by the dissolution of the limestone, dolomite and the gypsum rocks and is characterized by the underground drainage system of the sinkhole sand the caves. The study of this region is important for the petroleum geology and the 50% of the reserves are found here is thus zone.
<u>Carbonic acid is the cause of these features, as rain passes through the earth's atmosphere and picks up the carbon dioxide and dissolves it with water.</u>