How come you only need half of a strand of DNA to make a complete new one?

According ti the following map, what are the most common mineral resources found in the united states?

Acharreadas is a popular mexican thing where people display varying skills of horsemanship much like what events in the united states?

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.