The ozone layer that protects life on Earth

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The ozone layer that protects life on Earth

by raj44 » Fri Dec 12, 2014 6:08 am
2. The ozone layer that protects life on Earth from harmful UV rays is showing promising signs of recovery, according to a report issued by the UN Environment Program and the World Meteorological Organization. Although levels of ozone depletion remain high, the rate of depletion has not increased for over a decade and in some places there are signs of the layer thickening.
Which of the following, if true, most strengthens the above argument?
A. CFCs and similar compounds deplete ozone because when they reach the stratosphere, UV light breaks them down to release chlorine or bromine atoms, which in turn form active species that react with ozone.
B. Although the most potent ozone-depleting compounds have been phased-out and their emissions have declined considerably, many of them are quite inert and it will take between years and centuries before they are fully removed from the atmosphere.
C. Current depletion is still high but has not gotten worse for over a decade now.
D. The latest report compiled by around 300 scientists as part of an Ozone Treaty requirements suggests that the ozone layer is on course for recovery thanks to the ban of culprit chemicals.
E. About 90 percent of CFCs currently in the atmosphere were emitted by industrialized countries in the Northern Hemisphere, including the United States and Europe.
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by akhilsuhag » Fri Dec 12, 2014 3:03 pm
Hey Raj. Could you quote the source for this?
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by mbawisdom » Sun Dec 21, 2014 8:53 am
D supports the proposition in the statement.