Q3 - Hemoglobin, a substance in human

[r1r200]

I was just wondering why it can't be E. Is it because it says it picks up the oxygen in or near the lungs but the stimulus says "transports oxygen from the lungs to the rest of the body"?

[giladedelman]

Thanks for posting!

I think the problem with (E) is that it says "each hemoglobin molecule in human blood." The stimulus tells us that hemoglobin does a certain thing, but it doesn't say that every single hemoglobin molecule performs this task. Maybe some hemoglobin molecules are just kind of chilling out! We don't know.

Does that answer your question?

[tamwaiman]

Is (A) incorrect because "probably"? I consider probably is stronger than possibly, but both are different from always.
Thank you.

[giladedelman]

That's right! We know that hemoglobin get better at picking up oxygen with each oxygen molecule they grab, but that doesn't mean a hemoglobin with three molecules will probably pick up the fourth. Why? Because "probably" means "more likely than not." All we know is that it's more likely than if it only had two oxygen molecules. But that still might only raise its chances from 15%, say, to 20% -- well short of "probably"!

So that's why (A) is wrong.

(B) is out because although the shape seems to be a factor, we don't know whether there are other factors at play.

(C) is correct because it's basically paraphrasing the stimulus: as a hemoglobin picks up more oxygen, it gets better at picking up even more.

(D) is just super duper out of scope. We have no clue about this.

(E) is incorrect, as discussed above, because we don't know that every hemoglobin molecule gets in on the act.

Does that answer your question?

[lizard82]

I still have some question about why C is correct. If C states that"a HM that has picked up three oxygen molecules will be more effective at picking up another oxygen molecule than will THIS HM that has picked up only one oxygen molecule.", I think C is 100% right, because when stimulus say "more effective" it only compares a HM to itself. However, in C, you could see a HM compared to another HM. So C is possibly a wrong conclusion. Consider the following scenario, a HM that has picked up 3 OMs became more effective from 10%(none) to 20%(1OM) to 30%(2OMs) to 40%(3OMs), but another HM could became more effective from 40%(none) to 50%(1 OM) if the second HM have a higher initial efficiency.

[giladedelman]

You're right; that is conceivably possible. But read this carefully: we are NOT LOOKING FOR THE 100% CORRECT ANSWER. We're looking for the answer that's most strongly supported. Do you agree that that's (C) in this case?

[giladedelman]

You're right; that is conceivably possible. But read this carefully: we are NOT LOOKING FOR THE 100% CORRECT ANSWER. We're looking for the answer that's most strongly supported. Do you agree that that's (C) in this case?

[aznriceboi17]

Hi, could someone explain their thought process on choosing between C and E? The reasoning in C, as lizard82 and giladedelman pointed out, is not necessarily correct (there are examples of other LSAT questions that asked the test taker to identify this kind of flaw, ex: q23-the-higher-the-altitude-t4640.html).

However, as giladedelman pointed out, E is somewhat of a stretch because it talks about each hemoglobin molecule performing that function.

So C and E both have some drawbacks, how does one choose C over E? I guess the official answer would argue that the flaw in C is a less egregious one, but since they tested our ability to identify it in Identify the Flaw questions in the past, that doesn't seem that convincing.

[sumukh09]

Hm, I would argue C does not have any drawbacks and is the clear winner here.

The stimulus says hemoglobin molecules are more effective at picking up additional hemoglobin molecules with each molecule that it picks up, as long as the number of molecules is less than 4.

C) says exactly this without any confusion or ambiguity as to what it means. A hemoglobin molecule that has picked up 3 will be more effective at picking up that 4th molecule, because as the stimulus states in that second sentence, a molecule that has "X+1" number of molecules, provided that X is less than 4, is more effective at picking up an additional molecule than is a molecule that has only X hemoglobin molecules.

E) is wrong for the reasons stated above - the stimulus never says that "each" or "every" hemoglobin molecule transports O2 to the rest of the body.

[ohthatpatrick]

Although I initially had the same reaction as Sumukh, I do see how (C) isn’t 100% locked in because the original rule is unclear as to whether it says
"any hemoglobin w/ 3 oxygen is more effective than any hemoglobin w/ 1 oxygen"
vs.
"a hemoglobin molecule w/ 3 is more effective than it was when it had 1"

An easier metaphor for the wiggle room might be this rule:
"With each additional hour of studying, a student becomes better at taking the LSAT"

This would not allow us to prove that Gary, who has studied 10 hours, is better at the LSAT than Sheila, who has only studied 5 hours, because maybe Sheila started off from a loftier initial perch.

It only allows us to prove that Gary is now higher than his starting point, and Sheila is now higher than her initial starting point.

But the context of hemoglobin molecules being a simple biological construct makes it a more likely that we can treat them uniformly (as opposed to LSAT students, who start out as unique snowflakes).

Nevertheless, we have NO support for (E). Where does it say that every hemoglobin molecule picks up at least one molecule of oxygen?

Is there any sentence that could be interpreted to mean that?

So if you’re waffling between (C) and (E), you’d have to pick (C) for which there is some (albeit ambiguous) support vs. (E) for which there is no support.

You might also be bailed out / well-informed if you know that on Inference questions (particularly "˜most strongly support’ ones), the correct answer loves to reinforce the causal mechanism described in the stimulus ... whereas on ALL Inference questions, extreme language such as "each" is super sketchy.

[kenneth.ng.4]

Just wanted to add (E) states that each hemoglobin picks up one to four oxygen molecules. There is a chance a hemoglobin molecule picks up zero oxygen molecules, thereby making (E) an incorrect statement.

[keonheecho]

So for future reference, if we see the statement like the one we saw 'hemogoblin, a substance in the human blood, transports oxygen..." Is it safe to assume that the author is only speaking in general terms, and he is not trying to indicate that every hemogoblin acts this way? So it cannot be converted to a sufficient condition, it would have to be converted to 'most hemogoblin'?

What's troubling to me is that it seems like a similar line of reasoning used to eliminate (E) can also be used to eliminate (C). If (E) is wrong because we have no way of knowing that each molecule picks up 1 to 4 molecules, can't we also say that we have no way of knowing that
each hemogoblin molecule becomes more effective to begin with? Or does 'a hemogoblin molecule' (line 3) imply 'any hemogoblin molecule'?

thank you

[ohthatpatrick]

You can interpret the first sentence to refer to all hemoglobin molecules, just as you can the 2nd.

The problem is I can say, "All buses transport humans", but I still can't infer that "Every single bus has at least one passenger on it".

The first sentence is saying that the function of hemoglobin is to transport oxygen. We can't read it as a permanent trait .. i.e. "hemoglobin constantly has oxygen with it".

Given that it's a transportation device, you actually expect that when hemoglobin reaches other parts of the body, it deposits the oxygen there and then returns to the lungs, empty-handed.

I could say of "Breaking Bad",
Humans love this show. With each season you watch, you become more and more sucked into the story of Walter White.

But does that mean that I, as a human, must have seen at least one season of "Breaking Bad"?

No. (I haven't.)

But it DOES mean that every human who has gotten to season 3 is more enthralled than one who is merely done with season 1.