#14 - In 1980 there was growing concern that the protective

[biskam]

is the reason D is correct because it shows that the ozone layers could be unconstant (could've increased) while B is incorrect because seasonality differences could still mean that the overall numerical numbers re ozone could still be constant?

thank you!

[Adam Tyson]

Exactly right, biskam! If the ozone moves around, getting thinner in some places and thicker in others, then information about total ozone would not really help the government in response to a concern about thin or depleted ozone at the poles. Answer D does nothing to weaken the FACT about the total ozone, but it does weaken the RELEVANCE of that claim. Answer B, meanwhile, does nothing to either that fact or its relevance.

Well done! Keep it up!

[biskam]

Thank you! These #% questions are tough, but have to keep trying

[jona_zx]

Got it right but im unsure what the actual point of the gov officials is. Do they mean that since the global ozone is constant, this shows that it is not true that the ozone in the pole is lowering. Or do they mean that even if the ozone has lowered in the pole, this is irrelevant since the global total is constant and this is what matters.

[Jeff Wren]

Hi jona,

Unfortunately, the government officials don't provide us with an explanation for why they believe that the fact that global ozone levels have remained constant means that the concerns about decreasing ozone over the Antarctic should be dismissed.

Of the two possibilities that you mentioned, I expect the more likely one would be that they have (mistakenly) assumed that ozone levels are constant throughout the world, and so they believe that the ozone over the Antarctic has not decreased. If that is the assumption that they are making, then Answer D weakens their argument by indicating that the ozone levels are in fact not constant throughout the world, so the decreased ozone levels over the Antarctic might actually be a serious problem for life in that area even if global ozone levels have remained constant.

The other possibility is that the government officials don't really care that the ozone over the Antarctic has decreased so long as it doesn't affect the rest of the world. This seems less likely to me, and Answer D wouldn't necessarily weaken this argument because the officials would reply, "Who cares what happens in the Antarctic? We don't live there, so it's not our problem!" Of course, this strikes me as a very bad argument/extreme point of view for many reasons, which is why I expect that the first possibility is what the test makers were implying.