Question

question 5 (5 points)
listen
which of the following is not human - caused groundwater pollution?
a) water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking.
b) water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.
c) water in an aquifer is contaminated by leachate that seeps into the ground from a landfill.
d) water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock.
question 6 (5 points)
listen
which features are usually associated with karst topography?
a) lakes and wetlands
b) caves and sinkholes
c) plains and plateaus
d) mountains and valleys

Explanation:

For Question 5: Hydraulic fracturing, septic - tank drainage, and landfill leachate are human - caused sources of groundwater pollution. Dissolving of elements from surrounding rock is a natural process.
For Question 6: Karst topography is characterized by features formed by the dissolution of soluble rocks like limestone. Caves and sinkholes are typical karst features. Lakes and wetlands, plains and plateaus, and mountains and valleys are not the defining features of karst topography.

Answer:

Question 5: D. Water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock.
Question 6: B. Caves and sinkholes