The number of people served by advanced wastewater treatment plants doubled between 1968 and the mid-1990s, but because the treatment plants _______, the quantity of waste emitted into the water after treatment _______.
A) became so much more effective; decreased by about one-third
B) became so much less effective; increased by about one-third
C) remained ineffective; remained the same
D) moderately improved; increased by 10%

Question

Quizplus · Accepted Answer

The correct answer is A because if the treatment plants became much more effective, even though the number of people served doubled, the efficiency of the plants would result in a decrease in the quantity of waste emitted into the water.

The Number of People Served by Advanced Wastewater Treatment Plants