Placer mining where miners sift through material in riverbed deposits by using running water to separate lightweight mud and gravel from heavier minerals of value.

Which of the following statements is TRUE regarding the future risks of decadal (11-year) and multidecadal (35-year) droughts in the southwestern U.S. and Great Plains?

Which energy alternative has the side effect of depriving soil of the nutrients it would receive from the natural decomposition of plant matter, leading to a depletion of soil fertility?

Select all correct answers. Why have atmospheric carbon dioxide levels risen to levels that are far higher than it has been in more that 800,000 years.

Select all correct answers. The pillars of sustainability are

One way to improve sustainability of plants and landscaping is to plant non-native species.

This is the term for the systematic change in Earth’s climate, such as temperature, precipitations, and storm intensity. 

___________________ is the study of the interaction of humans with the natural environment.

The figure below is an example of ____________, which involves using devices to focus, move, or store solar energy.   

Select all correct answers. Select the environmental impacts from coal extraction.