Clastic sedimentary rocks are primarily classified on the basis of

Gold is not now being extracted from seawater. why not? a. it would be too disruptive to marine life to develop any marine mineral resources b. there is no gold in seawater c. we don't know how to extract minerals from seawater d. it would be too costly and difficult to separate the small amount of gold from the very large amounts of halite and other minerals

Alow-pressure belt means the air is cold and dry warm and rising cold and sinking warm and moist

During which era in earth's history were the first insects? mesozoic precambrian cenozoic paleozoic