Despite temperatures of more than 5,000º f, earth's inner core is solid because of
a layer of ice just above it. the fact that earth rotates so quickly. a thickness of over 1,000 miles. great pressure from the layers around it.

by using  production possibilities graph.  opportunity costs are key expenses in financial matters and are utilized as a part of registering money saving advantage investigation of a venture. such expenses, be that as it may, are not recorded in the record books but rather are perceived in basic leadership by processing the money costs and their subsequent benefit or misfortune.