Where was yam first discovered. Where is the origin of yam?
Glacial Activity: During ice ages, glaciers can carve out depressions in the Earth's surface, which can then become filled with water when the glaciers retreat. The Baltic Sea and the Great Lakes in North America are examples of seas formed through glacial activity.
Subsidence: Some seas are formed when the land sinks due to geological processes. This subsidence can create low-lying areas that become flooded by seawater. The Caspian Sea and the Dead Sea are examples of seas that formed in this way