Which of the following represent human systems?

1. cascade tunnel
2. coal mines
3. rocky mountains
4. the erie canal
5. lake superior

What are the similarities and differences in the way geologists and biologists approximate the age of the earth? justify your response in two or more complete sentences.

In the von thunen model of agricultural land use, what is produced closest to the city epicenter? a. dairy, vegetables, and fruits b. field crops, such as corn and wheat c. beef and other animal products d. wood and lumber

Fossil fuels such as coal, oil, and natural gas were formed over millions of years by