How can we use rocks to determine how an area used to look in the past?

We can use rocks to determine if the animals from to day have changed from the past.
Rocks also help us know if rivers once flowed through an area.
We use them to find out what type of animals live then that are extinct now.

One way the government of Kim Jong II controls the lives of the people who live in North Korea is by controlling information its people receive from the outside world. The correct option among all the options that are given in the question is the second option or option "c". People will remain satisfied with the developments that are going on in the country and they would never revolt.