Q8 - Scientists conjecture that certain microbes consume

[jgmartin82]

PT68, S2, Q8 (Inference)

(C) is correct.

We get a few pieces of information here; let’s look at them:

Certain microbes consume org. molecules, removing oxygen and generating CO2
CO2 promotes global warming
These microbes reproduce faster in higher temperatures

We’ll want to note some boundary words here as well. The first and third statements are conjectures (unproven statements), and "˜evidence indicates’ that CO2 promotes global warming.

It seems as though we could piece these premises together to come up with a grand conclusion that follows from all of the statements. Doing this is dangerous, as we may infer too far, and it is potentially a waste of time, as the answer choices may not demand that we do that. Instead, let’s hold the premises in our head and evaluate each answer choice. Into the answers:

(A) is not supported by the statements. Must this be true? Well, what do we know about organic molecules? We simply know that the microbes consume them. Does this mean they’ll be depleted soon? Spiders eat mosquitoes, does that mean they’ll be a shortage of mosquitoes soon? No, though we can hope. Eliminate.

(B) is not supported by the statements. Every organism? We only learned about the microbes. Humans are organisms that produce CO2, do they reproduce more quickly at high temperatures? On second thought, don’t answer that, the point is we can’t know one way or the other from the given facts. Eliminate.

(C) Seems to follow from the premises. The microbes produce CO2, which in turn promotes global warming. However, we should be a little nervous about the certitude here: it will be exacerbated.Do we know this for sure? We just have a bunch of conjectures. Let’s keep it for now and see what (D) and (E) give us.

(D) is not supported by the statements. We know they remove oxygen. Do they remove other things? No idea. Eliminate.

(E) is not supported by the statements. There’s no way to know how much CO2 the microbes are putting into the Earth’s atmosphere. We just know that they generate CO2; there’s no indication of their number or how much CO2 they produce. Eliminate.

We’re left with (C). As we noticed, it’s not 100% provable. We went from premises with conjectures to a conclusion of what will be. This is often the case with inference questions that ask for what is most provable or most supported. It’s good to have your radar up and notice that the answer choice isn’t totally provable, but keep in mind that it’s common for the right answer choice to be something a bit less than airtight.

[zainrizvi]

We actually don't need to have that initial hesitation for (C) as the question states "the scientists' conjectures, IF TRUE"

[logicfiend]

(A) is not supported by the statements. Must this be true? Well, what do we know about organic molecules? We simply know that the microbes consume them. Does this mean they’ll be depleted soon? Spiders eat mosquitoes, does that mean they’ll be a shortage of mosquitoes soon? No, though we can hope. Eliminate.

As a note, we're not looking for an answer that must be true, only that it is most strongly supported by the stimulus.

If I understand your analysis correctly, I don't think what you said of (A) is actually correct. (A) isn't implying that the organic molecules will soon be depleted because of the microbes' activity. It's saying that if they are depleted, the microbes' activity will diminish. This is incorrect because we have no reason to think that if these organic molecules are depleted, the microbes couldn't be removing oxygen and converting it into CO2 through the consumption of something else. Like you said, this is a conjecture, so there's way more doubt in this statement than the more concrete 2nd sentence in the stimulus.

[linda.ning.an]

Why is answer choice A) wrong?

Microbes feed off organic molecules in shale and sediments, so when organic molecules in exposed sediments are depleted, microbes' activity will also soon diminish.

Please help me with this question. Thank you.

[snoopy]

Why is answer choice A) wrong?

Microbes feed off organic molecules in shale and sediments, so when organic molecules in exposed sediments are depleted, microbes' activity will also soon diminish.

Please help me with this question. Thank you.

We don't know if these certain microbes also consume something else (i.e. inorganic molecules) to sustain its activity. This is an inference question, and we cannot infer that the microbes' activity will diminish as soon as organic molecules are depleted since we don't know if their activity is dependent on consumption of organic molecules.