【单选题】One of the most pressing challenges that the United States--and indeed, the world--will face in the next few decades is how to alleviate the growing stress that human activities are placing on the env...
A.
there are many more ways in which humans are hurting the environment.
B.
environmental degradation is continuing unabated.
C.
the total of animal and plant species facing extinction are too numerous to list.
D.
in addition to fish, many other plant and animal species face over-exploitation by humans.