Answer: This region is one of the world's premier natural showcases for Earth history. These rocks formed deep beneath the surface of the earth and were uplifted, eroded, and exposed for eons. By 600 million years ago North America had been eroded to a remarkably smooth surface.
Explanation:
I believe the answer is: survey
When doing a survey, We collect information from group of subjects by making them answer a set of questionnaire,.
This type of data collection method usually really subjective but it could provide a more accurate/in depth data from the subjects/
We can get information about other nations through various books, newspapers, atlas and tourists who come to visit our country.
