Question: Scientists frequently monitor levels of microorganisms at beaches in the summer time. High temperatures, pollution, runoff, and illegal dumping all affect water quality. What do these scientific efforts illustrate?

  Options: 
 A. Pollution can be eliminated through water testing.
 B. High temperatures increase runoff from agricultural fields.
 C. Water testing identifies origination of illegal dumping.
 D. Monitoring water quality is important to public health.
Answer: D