The question is incomplete. The complete question is as following:
Conservation biologists are scrambling to put measures in place to contain the spread of lionfish. For example, Stephanie Green and colleagues measured how quickly the number of native fish would recover if varying numbers of lionfish were removed from reefs in the Bahamas. They randomly assigned 24 reefs to one of four groups and plotted the proportional change in the number native fish at six-month intervals after different amounts of lionfish (0%, 25%, 75%, or 95%) were removed. (In the graph that follows, values above 1 on the y-axis represent amounts that exceed those at the start of the study in 2009, while values below 1 indicate declines.) Compare the percentage of native fish observed in June 2011 after 25 percent versus 95 percent of lionfish were removed. What is the take-home message?
a.Removing even a few lionfish helps native fish recover.
b.Removing just a few lionfish does not help much; many of the invasive fish must be removed to help native fish recover.
c.Removing even a great amount of lionfish does not help native fish recover.
d.The biologists must find another way.
Answer: b.
Explanation:
The June 2011 green (top) data point indicates a proportional shift of about 1.7, which means that the native fish population shows very good recovery by about 70 per cent when 95 per cent of the lionfish were eliminated. By comparison, the orange (bottommost) data point at June 2011 indicates a relative shift of about 0.5, which means that when only a quarter of the lionfish were removed the native fish population decreased by about 50 percent (a result that was almost the same as when none of the lionfish were removed).
Hence, the correct option is B.
