#15 - Few, if any, carbonated beverages contain calcium

[Administrator]

Complete Question Explanation

Weaken, CE. The correct answer choice is (A).

In this question, you are asked to weaken a causal conclusion, specifically the conclusion that caffeine consumption is probably the primary cause of the higher incidence of broken bones in teenagers who drink large amounts of carbonated beverages with caffeine than in teenagers who do not.

The author of the stimulus bases that causal conclusion on an observed correlation in teenagers between drinking carbonated beverages containing caffeine and broken bones. The argument's premises shed light on how consuming caffeine might be a cause of broken bones, by telling us (1) that consuming caffeine causes people to excrete significantly more calcium than they would otherwise, and (2) that calcium deficiency can make bones more brittle.

The author has inappropriately assumed that a calcium deficiency in teenagers who drink carbonated beverages is primarily caused by the caffeine in those beverages, and not by something else. The conclusion will be undermined if an answer choice shows that such teenagers experience calcium deficiency for some reason other than drinking the caffeine in carbonated beverages.

Answer choice (A): This is the correct answer choice. The answer poses an alternate cause of the calcium deficiency in teenagers who drink carbonated beverages with caffeine. Rather than being calcium deficient because caffeine causes them to excrete calcium, the answer suggests these teenagers are calcium deficient (relative to their peers) because they are consuming less calcium.

Answer choice (B): This answer choice is irrelevant. The conclusion is about the "higher incidence" of broken bones in a certain teenage group (those who drink caffeine-containing carbonated beverages) versus another teenage group (those who do not drink such beverages). Comparing teens to older and younger people sheds no light on the specific comparison the conclusion addresses.

Answer choice (C): This answer choice is too weak to have any impact. Just because at least one teenager has a non-caffeine related calcium deficiency does not suggest that, overall, caffeine consumption is not a primary cause of broken bones. In other words, a single outlier cannot disprove evidence from an average.

Answer choice (D): This answer choice is irrelevant. The stimulus tells us some of the more popular carbonated beverages contain "significant amounts of caffeine." The fact that non-popular carbonated beverages contain even more than that "significant amount" doesn't undermine the premise, and therefore does not weaken the conclusion.

Answer choice (E): This answer choice is irrelevant. We do not know the amount of calcium consumed by either group of teenagers referenced in the argument, so this answer choice cannot affect the argument.

[cargostud]

I selected (B) for this one since it seemed to make the most sense to me at the time. Although the correct answer is (A), I can't seem to wrap my head around why. It almost seems to agree with the stimulus. I wouldn't go so far as to say it strengthens the argument, but to me it doesn't really weaken it.

In summary; Few, if any, carbonated beverages contain calcium and some popular ones contain lots of caffeine, which causes people to excrete calcium. Teenagers who drink this stuff suffer more broken bones due to calcium deficiency caused by the caffeine consumption.

[Jeremy Press]

Hi cargostud,

We've just posted the explanation to this question above. If you still have questions after reviewing it, please let us know!

Jeremy

[KhaliaCWilliams]

Would B have been right if it said something like "Teenagers who drink large quantities of caffeine also engage in the types of activities that carry a high risk of causing broken bones much more often than teenagers that do not?"

[James Finch]

Hi Khalia,

Both (A) and (B) are presenting alternate causes, the most common way to weaken a causal argument. So yes, your edits would make (B) correct, as the major issue with it is that it doesn't distinguish between teenagers that drink a lot of caffeine and those that don't, the two groups we're dealing with in the stimulus. (A) does, and that's what makes its alternate cause better than (B)'s; it's dealing with the specific types of teenagers rather than teenagers as a whole.

Hope this helps!

[saygracealways]

Hi Powerscore,

I understand why (A) is the correct answer choice, but am struggling to eliminate (E).

I picked (E) because I thought this meant that teens who drink lots of caffeinated carbonated beverages (CCB) and consequently secrete significantly more calcium (than teens who don't drink CCB) would tend to ingest more calcium as a part of their regular diet. By ingesting more calcium as a part of their regular diet, they won't have a calcium deficiency (basically the calcium ingestion from their regular diet offsets the calcium excretion from drinking CCB), so calcium deficiency is unlikely to be the primary cause of broken bones in these teens.

Is my reasoning incorrect because:
1) "The more calcium ingested as part of a person's regular diet, the more calcium that person tends to excrete" DOES NOT MEAN "the more calcium a person tends to excrete, the more calcium that person ingests as part of his/her regular diet"? I thought this is a correlative statement, so the order can be reversed, but would it be a logical error to make this reversal?
2) Even if (E) could be taken to mean "the more calcium that person will tend to excrete, the more calcium the person ingests as a regular part of his/her diet", I cannot assume that therefore there is no calcium deficiency?

Thank you so much!

[Jeremy Press]

Hi grace,

You've correctly suggested that you can't reverse the relationship in that correlative statement. Think of a simple example: "The more sports a person plays, the more exercise they get." Now let's say I know that my neighbor gets a lot of exercise. Do I know anything certain about how many sports they play? No, because there could be many ways to get exercise. My neighbor's exercise level could be due to them doing at-home calisthenics, or Peloton, or whatever. So we don't know that the teenagers who excrete more calcium in the stimulus (because of their drinking more caffeine) also have more calcium in their diets.

On your second question, the answer is that it's true that you cannot assume that, so you still wouldn't get a weakening effect from answer choice E (nice job noticing that, by the way!).

I hope this helps!

[Henry Z]

We’re told that “consuming caffeine causes people to excrete significantly more calcium than they would otherwise.” (A) suggests that the amount of calcium these teenagers consume doesn’t make up the amount they excrete, so it’s still the case that the caffeine is prolly the primary contributor to their calcium deficiency. It’s like one investor loses a huge amount on stock X, while earns a little on stock Y, it’s only reasonable to say that the primary cause of his total loss is stock X, not stock Y (which in fact offsets loss). It baffles me how drinking not enough calcium-rich beverages, by which you're getting MORE calcium, can be seen as a cause of calcium deficiency. To me, (A) strengthens the conclusion, that caffeine really takes away too much calcium.

I chose (E) because I think it offers an alternative cause. It shows that caffeine is not the only thing that makes you excrete calcium. I read the explanation above but I think since the basic assumption of a causal argument is that the purported cause is the only one, we don’t have to know if these teenagers really ingested more calcium. (E) weakens simply by refuting that basic assumption, doesn't it?

[Adam Tyson]

Answer E tells us nothing about why the teenagers who drink a lot of carbonated caffeinated beverages have more broken bones than those who do not, Henry. The author thinks the caffeine is the cause of that difference, and answer E gives us no reason to doubt that. Teenager A drinks more calcium than teenager B, and teenager A excretes more calcium than teenager B. Now, which teen is drinking more carbonated caffeinated beverages? Which one is breaking more bones? This answer gives us no useful information about those things.

Answer A weakens the argument by suggesting that the caffeine is not the primary cause of the difference between the two groups. Instead, the difference is that the ones breaking more bones are also the ones who consume less calcium in the first place. It's not "more caffeine," but "less calcium" that is the true cause. Caffeine consumption may be a secondary cause (further lowering an already low amount of calcium) rather than a primary cause.

[Henry Z]

Thanks Adam.

I just reread the causal reasoning section of the LR Bible and it says "if you are asked to weaken a possible or probable cause conclusion, presenting an alternate cause will often not be effective." Is that the case of (E) here? Apart from your explanation above, can we also eliminate (E) because the stimulus is not a basic causal argument, but a probable cause argument?