Ozone has potential negative impacts on human health and vegetation, and also acts as an important greenhouse gas. Background ozone levels in western Ireland have shown a steady increase over the past two decades. During the same period, the relative contribution to these increasing ozone levels from air over the North Atlantic has also significantly grown. Deposition of ozone to surface ocean waters via physical uptake and chemical reactions in the surface layer likely constitute a significant, albeit highly variable “buffer” curtailing the rate of ozone increase in this region. Past tests have shown the ocean surface to be adept at absorbing ozone from the surrounding air. But researchers have recently completed studies that show that the ocean near the coast of western Ireland has surprisingly low levels of ozone at the surface.

1. Which of the following, if true, best reconciles the apparent discrepancy presented in the passage?

A) Certain corn plants have been shown to have a higher yield in areas with a greater ozone concentration than normal.
B) Historical ozone measurements in Ireland were made with an outdated, less accurate methodology.
C) Ozone levels in the North Atlantic, though higher than the world average, have been shown to have no harmful effects on birds native to that region.
D) Ozone, once absorbed by the surface of the ocean, can migrate to surrounding environments.
E) Once the ozone concentration in a region reaches a certain level, it is difficult for that region to retain more ozone.



2. In the context in which it appears, “adept” most nearly means

A) proficient
B) adaptable
C) inept
D) mundane
E) deficient



3. The author of the passage mentions the background ozone levels in western Ireland primarily in order to

A) provide context in which to consider the findings of the recent studies
B) argue in favor of curtailing processes that add greenhouse gases to the environment
C) indicate that western Ireland is a unique region in that its ozone concentration has risen steadily over the years
D) assert that the buffering effect of the ocean in the region may be due to surface temperature
E) support the correlation between the ocean’s buffering effect and the levels of background ozone in western Ireland