Exam 23: Periodic Table of the Elements

A(n) is a solid aggregation of _.

Once the contaminants have been removed from the fracking wastewater, the water can be reused for additional drilling. One problem created by using this technique to purify fracking wastewater is that _.

Subsurface mining is used extensively in the extraction of _.

If you want to avoid buying a "blood diamond," you should avoid purchasing .