#16 - Must Be True

[pacer]

Can you please go over passage 3, with regards to Q16?

I am confused with which hypothesis it the question stem referring to. In the first paragraph, 2 opposing views are presented, followed by the author's view at the end of the paragraph which seems to agree somewhat with both opposing views.

opposing view 1 = level of CO2 will increase in the future and contribute to global warming
opposing view 2 = increase in CO2 will increase photosynthesis which will decrease global warming

Author's view = sure, there will be increases photosynthesis (increase vegetation) which will decrease CO2 and the level of CO2 will increase at ta slower rate (meaning that it will indeed increase but just slower than thought by some experts). So, to me it seems that the author is somewhat agreeing with both the opposing views presented earlier in the paragraph


I know that Q16 is asking for a flaw - something that they have failed to consider when hypothesizing something

I am not sure what hypothesis is it referring to.

I thought that when it mentioned the "effects of increased vegetation" - the author points out in paragraph 2 that the types of species making up such vegetation differs - so this might have been something that has been overlooked - which led me to choice D.

Choice B is something that comes at the very end of the passage and I don't see its connection to the first paragraph.

Can you go over this question and the relevant parts of the passage?

Thanks!

[Emily Haney-Caron]

Hi pacer,

The hypothesis the question is referencing begins with, "some research has suggested." The way we know this is because we are told it is the hypothesis that predicts "the effects of increased vegetation on the rate of global warming," and because THAT is the hypothesis in the first paragraph that the passage suggests is not accurate. The passage is saying that, overall, the experts' expectation from that first sentence is probably more accurate.

You want to think about which of these overall weakens the hypothesis that CO2 won't increase very quickly. The discussion of the decomposition of peat does just that - it shows that, even if plant growth increases, decomposition more than counteracts the increased growth. The other answers to not provide a reason why increased vegetation would slow global warming: they are either not focused on CO2 in particular, or actually support the hypothesis rather than weaken it.

Does that help?

[pacer]

Can you go over the individual answer choices in more detail?

I get now that the hypothesis is

increased CO2 -> increased photosynthesis -> decreased global warming

Choice A = restates this hypothesis (strengthens)
Choice B = increased photosynthesis may not lead to decreased global warming
Choice C = Not relevant to this hypothesis
Choice D = restates the hypothesis (strengthens)
Choice E = not sure - why is this wrong?


Since the question stem states "fails to take into account - does this mean this is a flaw in reasoning type question?

[BethRibet]

Hi pacer,

This question is simply asking which of the answer choices best describes the author's critique of the hypothesis in the first paragraph. The hypothesis is that increased CO2 could ultimately decrease global warming, due to increased plant growth.

The critique (lines 53-55), states exactly what's in answer choice B, giving us the author's explanation of what the hypothesis missed -- the important point being that global warming will not decrease (for the reason the author states).

None of the other answer choices so clearly identify what the author says is missing from the hypothesis, and that's why you can rule them all out.

Hope this helps!
Beth

[lsatquestions]

I'd like to go over the wrong answer choices as well... find that more helpful than just saying they're wrong.

I was stuck between B and D, but eliminated D because the hypothesis is not concerned with distribution of peat. Do you mind confirming my thinking as per the below:

A) In line with hypothesis
C) false - high latitudes will experience more warming + not relevant
D) not concerned with distribution of peat
E) in line with hypothesis

[Adam Tyson]

The question is specifically about why increased CO2 will not reduce global warming. The idea is that more CO2 will mean more plants, and plants will absorb the extra CO2 and eventually slow global warming. In the third paragraph the author rebuts this argument by showing that it fails to take into account the melting permafrost and decomposing peat. That should be the prephrase, and that matches answer B.

A is wrong because photosynthesis is not impacting global warming. The argument about increased photosynthesis is about increasing agricultural abundance, and so this answer addresses the wrong thing. Remember, the question asked for what the argument failed to consider with regard to global warming, not what it failed to consider with regard to plant growth.

Answer C is incorrect for at least two reasons, the first of which is that the author said the opposite was true. It's the high latitude habitats that will get the greatest temperature increases. But it also fails to address what the question asked for: why is the argument about global warming incorrect?

Answer D is wrong for at least two reasons. First, it mixes up the two arguments, smashing them together in a way that the author never suggested. A change in the plant mixture is not related to the issue of decomposition of peat; it's just another consideration. And there wasn't a problem with the distribution of peat, but with an increase in the decomposition of it. Distribution and decomposition are not the same thing.

Answer E is incorrect because the argument didn't fail to take this into consideration. That was actually what the argument relied upon, so it DID take that into consideration! We need to know what the opposing argument failed to consider, not what it did consider.

I hope that helps clear things up for everyone!