PCBs (polychlorinated biphenyls) ________.
A. remain in the sediments for unknown periods of time
B. are no longer manufactured or used in the U.S
C. are still entering the environment from previous use
D. were in greatest use in the early 1960s
E. All of these are correct.
Answer: E
You might also like to view...
The number or variety of species found in a particular area is called
A. ecological diversity. B. species diversity. C. functional diversity. D. biodiversity. E. genetic diversity.
Which marine ecosystem has average net primary productivity comparable to a tropical rainforest?
A) Algae beds and coral reefs B) Estuaries C) Freshwater swamp and marsh D) Open Ocean E) Upwelling zone
Which of the above molecules contains a carbonyl group?
A. a B. all but d C. c D. all but b E. all but a
Scientists studying the Florida Everglades have found that between 2003 and 2011, there was a 99 percent decrease in raccoons, a 98 percent drop in opossums, a 94 percent drop in white-tailed deer, an 87 percent decrease in bobcats, and no rabbits or foxes were observed. Which has caused the collapse of mammals in this ecosystem?
A. pythons B. alligators C. hurricanes D. pollution