If we assume that (C) is talking about ocean water and snow-covered land, I agree that it would have to be true that snow-covered land would be heated less than non-snow-covered land given the same sun. And I agree that that's compatible with (C): water and snow-covered land could still heat the atmosphere, just by not as much as water and non-snow-covered land would.
But I still don't see how (C) would *strengthen* that reasoning. I read the argument (and your explanation) as being about what warms the atmosphere *more or less* than normal conditions. We know that everything warms the atmosphere: sun being reflected on land, ocean, ice, and snow; AND sun being absorbed by land, ocean, ice, and snow. The mere fact that the sun reaches earth warms the atmosphere; if there were no sun, it would not be warmed; even if Earth were all ice, the atmosphere would still be warmed more than if there were no sun at all. The argument is saying that the more reflection there is, the less warming there will be. Showing that "the less reflection (=more absorption) there is, the more warming there will be" would strengthen the argument, because it would show that relationship goes dynamically in both directions.
But (C) doesn't say that "the less reflection (=more absorption) there is, the more warming there will be." It simply repeated the premise: everything warms the atmosphere. No information about more or less. Thus no strengthening effect, imo.
Anyway, I agree that (C) is the best of bad answers if you give it as much help as I do many of my wrong answers!
#10 - The more sunlight our planet reflects back into space
We should read (C) to mean that, rather than just the land and ocean water temperatures rising more due to increased absorption of sunlight than ice and snow, in turn the warmer land and oceans heat up the atmosphere. This is not actually stated in the stimulus, although I think most test takers would assume it on first reading, so it isn't a mere restatement of one of the premises. And it clearly strengthens the conclusion directly, by making the opposite cause have the opposite effect.
Hope this clears things up!
Now I get it, this strengthen with CE belongs to second type, Cause doesn't occur then Effect doesn't occur strengthen CE type.
Like the poster above has said, does this mean that the answer (E) describes sort of the opposite of the conclusion that 'the greater the area of Earth's surface that is covered with snow and ice, the cooler, on average, the global atmosphere is likely to become'? The stimulus is more of a correlation but a causation, but the answer is similar to how questions with causal statements are strengthened by showing the absence of the cause with the absence of the effect.
Thanks in advance for all of your help on this. I've looked through the previous posts discussing answer choice (D) -- while, for example, I can see why answer choice (C) is correct, I'm unable to articulate why (D) is incorrect.
For me, answer choice (D) strengthened the argument as a "defender". In stating that the atmosphere derives most if its heat from the passage of sunlight through it, (D) rules out the possibility of the atmosphere being heated by, say, the earth's core or by heat released by trees (this last example is a made-up one, obviously, but you get the idea). If the atmosphere could be heated by these alternative sources, then the amount of snow (and the amount of sunlight reflected) could only have a negligible effect on the temperature of the atmosphere. Sure, it could cool the atmosphere a bit, but if the atmosphere does not derive most of its heat from sunlight coming through the atmosphere, then the global atmosphere won't necessarily become cooler if there's more snow covering Earth's surface.
In a way, I feel like (C) is just a more "specific" version of answer choice (D), which I think is why I'm having trouble definitively ruling out (D).
The way I read answer D, ntlsat, it could be a weaken rather than a strengthen answer. Consider this - sunlight that is reflected by snow and ice passes through the atmosphere twice (once on the way down to the surface, then again going back up due to being reflected). This would suggest that reflecting sunlight should warm, rather than cool, the atmosphere! At a minimum, snow and ice don't prevent sunlight from passing through the atmosphere, so this answer does nothing to add weight to the claim that snow and ice cool the atmosphere.
Adam M. Tyson
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