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#24 - Plant species differ in that renewed growth in spring

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Complete Question Explanation

Parallel Reasoning-CE. The correct answer choice is (C)

The stimulus states that there are two factors that can cause-- trigger-- renewed growth in spring: day length and temperature. Those factors can work together, or alone.

The stimulus concludes that since day length doesn't change for specific dates, species that widely vary the date on which they resume growth are responding at least in part to temperature.

The stimulus contains causal reasoning, but your main focus should be that the stimulus reaches its conclusion by eliminating a pure alternative. Very broadly speaking, the stimulus attempts to explain why something occurs, and the correct choice should as well. Also, the correct response must eliminate a pure alternative explanation. You should note that the pure alternative of day length alone is eliminated, but the stimulus leaves open the possibility that day length and temperature in combination are involved.

Answer choice (A): This choice does not contain an explanation, but a prediction, so this choice is wrong. Also, the fact that few physicians are willing to act as supervisors does not eliminate the option of working under the close supervision of a physician. That is because we have no idea how many trainees a physician can supervise, or how many trainees there are in the first place-- a few physicians could easily be enough. Furthermore, this choice does not suggest a possible combination.

Answer choice (B): Since this choice neglects the possibility that there will be no wind at all, and never explains what would happen in that case, there is a third alternative that this response ignores, and this choice is incorrect. Also, this choice contains no possibility of a combination.

Answer choice (C): This is the correct answer choice. This response contains two pure options and an option to combine, and proceeds to eliminate the idea that volume alone accounts for the cost. This means that the explanation for varying cost is that it depends in part or entirely upon weight.

Answer choice (D): This choice does not attempt to explain, but rather to predict, so this choice is wrong. Also, there is no option for a combination. The detectives cannot be the choices. For this response to be comparable there should have been discussion of a causal factor other than volume of business.

Answer choice (E): This choice is about increasing the probability of a successful solution, instead of about explaining an occurrence, so this response is incorrect. Even though this response offers choices and a combination, it does not seek to establish what the responsible factors are, but rather how to achieve a goal.
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This is parallel question.

While the correct answer is C, I chose answer E.

When I solved this question, I was fairly confident by excluding A-D right away.

I focused on the stimuli's description of "day length OR by temperature OR else by a combination of both."

Since A, B, and D did not include the combination as an option, and C connects premises with AND, I chose E right away.

The problem for me is, of course, that C is the correct answer even though it advances its premise with "AND" instead of "OR."

I need an deeper analysis how they parallel.
(I may have grasp of it, but need a clear insight)

Additionally, was it a problematic way of excluding answer A,B, and D based upon the fact that its premise did not provide an option of combination of two options?

Most importantly, what were the problems with answer E that was different from stimuli and the correct answer C?
Robert Carroll
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Sometimes the wording can be tricky. You notice the stimulus gives three possible causes for renewed growth: day length, temperature, or a combination of both. So plant species can be divided into three groups: those whose renewed growth is triggered by just day length, those whose renewed growth is triggered by just temperature, and those whose renewed growth is triggered by a combination of both. This is very similar to what choice C is saying. To confirm this, convert what C is saying into the language of the stimulus (we just showed that what the stimulus is saying can be converted to the language of C; doing this the other way around should make it clear that the corresponding premises in the stimulus and C are worded in an equivalent way):

Landfills differ in that what they charge companies can be determined by volume or by weight or by a combination of both.

Don't get hung up on the difference between "OR" and "AND" here. Examine the function of the list of three options. Those three options (day length, temp, or both) divide plant species into three groups. Landfills are divided into three groups, too, by what they use to determine what they charge: volume, weight, or both. Just like no species falls into an overlap between these groups, no landfill falls into an overlap. So the first sentence of the stimulus and the first sentence of C are saying the same type of thing.

Now examine the structure of the stimulus. Some species renew growth on different days, year by year. Since the length of a day, year by year, is the same, this excludes option 1 (can't be just day length). So it has to be option 2 (temperature only) or option 3 (a combination). C says some landfills charge different amounts for the same volume. So option 1 (volume alone determines charge) can't be true. So it has to be option 2 (weight) or 3 (a combination). In either case, weight (alone or combined with volume) determines the charge.

Now look at E. E does not have the structure "three options, one is excluded, so a feature of the other two must be true." E is actually not even saying that something is true, just that action should be taken - it's stating what should happen, not what is actually happening. So it's not parallel for that reason.

As to the rest, yes, the key to the correct answer here is that one option (day length alone) is not true, so a common feature of the other options (temperature, either alone or with day length) has to be contained in the remaining options. Only C matches the stimulus in this respect.

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Thank you so much!
I realized I should focus on structure mainly not the wording for parallel problems.