How old are the oldest rocks on the ocean floor?
a. less than 200 million years old
b. approximately one billion years old
c. approximately 500 million years old
d. between 200 and 500 million years old

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.