How is a nonconformity different from the other types of unconformities

Acivilization exists for several hundred yeaars, developing its own language. such a civilization probably has been: a. farming corn b. suffering from a lack of contact with the outside world. c. isolated by mountains or some other physical barriers. d. starving from lack of trade.

Find the percent of change from 500 oz to 800 oz

What tests were able to determine when continental crust was formed?