Lexikon

the karst is an underground or above ground landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite in the cavity of which water is circulating. The water source is generally rain water infiltrated from the surface. The karstification of a landscape may result in a variety of large or small scale features both on the surface and beneath. Karst landforms are generally the result of mildly acidic water acting on soluble bedrock such as limestone or dolostone. The carbonic acid that causes these features is formed as rain passes through the atmosphere picking up CO₂, which dissolves in the water. The karst has an important role is the formation and transmission on mineral waters. In Hungary for example the rain water infiltrated through the karst surface of the Northern mountains supply partly the drinking water in the wells of the Great Hungarian Plain area.

conversion of kilogram to other mass units:

conversion of kilometer:

a knowledge base is a special kind of database for knowledge management, providing the means for the computerized collection, organization, and retrieval of knowledge. Also a collection of data representing related experiences, their results are related to their problems and solutions.

Source: http://en.wikipedia.org/wiki/Knowledge_base