"Surprising" Phenomenon
Why are mixed-age classrooms effective today, even though they were ineffective in the past?
Objective
The correct answer should tell us something that is different about mixed-age classrooms today compared to the past that would positively impact children’s ability to learn.
A
On average, mixed-age classrooms today are somewhat larger in enrollment than were the ones of the past.
We have no evidence that larger enrollment is better for learning. In fact, larger classes suggest that students might get less attention, which could make it harder for children to learn.
B
Mixed-age classrooms of the past were better equipped than are those of today.
This is something negative about today’s mixed-age classrooms compared to the past. So, it’s not going to help explain why mixed-age classrooms today achieve better results.
C
Today’s mixed-age classrooms, unlike those of the past, emphasize group projects that are engaging to students of different ages.
This is something positive about today’s mixed-age classes compared to the past. More engaging projects might lead to less boredom for older students and more attention given to younger students. This is the only answer that says something remotely positive about today’s classes.
D
Today’s mixed-age classrooms have students of a greater range of ages than did those of the past.
We don’t know whether having a greater range of ages is a positive development for learning. There’s evidence it isn’t, because past results show older students were bored, and younger students were confused. Increasing the age disparity in class might hurt learning.
E
Few of the teachers who are reviving mixed-age classrooms today were students in mixed-age classrooms when they were young.
This says most teachers of mixed-age classes today are not students in mixed-age classes when they were young. This doesn’t tell me something positive about mixed-age classrooms today compared to the past.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the arrival of humans on Tiliga caused a decrease in the population and diversity of the island’s bird population. As support for this hypothesis, the author compares the top 50 cm of soil (which was accumulated over the 3,000 years since humans arrived) with the lower 150 cm of soil (which was accumulated over the previous 80,000 years). This comparison showed that before humans arrived, there was a larger and more diverse bird population.
Notable Assumptions
The author assumes that it was the arrival of the humans, not something else, that caused the decline in the population and diversity of birds. It could be that some thing else led to both the arrival of the humans and the decline in the bird population. We have a correlation between the arrival of humans and decline of birds, and the author is assuming a causal connection.
A
The bird species known to have been eaten by the islanders had few natural predators on Tiliga.
This reduces the strength of an alternate hypothesis (the alternate hypothesis being that predators may have been responsible for the declining bird population). Reducing the strength of alternate hypotheses is a way to strengthen arguments, so this does not weaken the argument.
B
Many of the bird species that disappeared from Tiliga did not disappear from other, similar, uninhabited islands until much later.
(B) says that birds disappeared much more slowly without humans. “Many” is too vague to make any strong inferences here, but this does give some reason to believe that the presence of humans is related to faster disappearance of birds, which is consistent with the argument.
C
The arrival of a species of microbe, carried by some birds but deadly to many others, immediately preceded the first human immigration to Tiliga.
This weakens the argument because it introduces an alternate hypothesis. (C) suggests that a microbe that arrived at the same time as humans could be responsible for the disappearance of the birds.
D
Bones from bird species known to have been eaten by the islanders were found in the underlying 150 centimeters of soil.
The birds that humans ate would have already existed (and died) on the island so it makes sense that their bones were found in the lower 150 cm of soil. This is consistent with the argument and doesn’t weaken the claim that humans caused a decrease in the bird population.
E
The birds that lived on Tiliga prior to the first human immigration generally did not fly well.
Information about birds’ abilities to fly is completely irrelevant to the argument.
Dodd: But the common name highlights the crucial fact that both are composed of the same material and have very similar structures; so it is acceptable as a scientific term.
Speaker 1 Summary
Chai claims that using the term “tree” to include both coniferous and deciduous plants isn’t sufficient for scientific use, even though it’s fine for day-to-day conversations. Why? Because the common term obscures the different origins of coniferous and deciduous plants.
Speaker 2 Summary
Dodd argues that using “tree” to mean both coniferous and deciduous plants is scientifically acceptable. Why? Because using the same term for both highlights their similarities in structure and material makeup.
Objective
We want to find something that Chai and Dodd disagree about. They disagree over whether it’s scientifically acceptable to include both coniferous and deciduous plants in the term “tree”.
A
it is advisable to use ordinary terms as names for biological forms in scientific discourse
Neither speaker makes this argument. Chai and Dodd are only talking about whether the specific term “tree” is scientifically acceptable, and neither comments on whether there’s a general rule about using ordinary names in science.
B
using the same term for two biological forms with different lineages can be scientifically acceptable
Chai disagrees with this, but Dodd agrees: this is the point of disagreement. Chai claims that “tree” is a scientifically unacceptable term specifically because it includes plants with different lineages. Dodd argues that it’s acceptable regardless.
C
both deciduous and coniferous plant forms evolved from simpler biological forms
Neither speaker directly makes this claim. Chai’s reference to “lineages” does imply that Chai agrees, though—but there’s no reason to think that Dodd would disagree.
D
it is important that the lay terms for plant forms reflect the current scientific theories about them
Neither speaker discusses this idea. Neither Chai nor Dodd talks about what goals lay terminology should accomplish, or whether or not those goals are related to science.
E
biological forms with similar structures can have different lineages
Both speakers likely agree with this. Although Chai doesn’t directly talk about structures, and Dodd doesn’t discuss lineages, neither one disputes the other’s factual claims about trees. This means they likely agree that trees have similar structures but different lineages.
Summarize Argument
The author concludes that headphone manufacturers would not help stop teen hearing loss by adding a line of headphones that turn off when a dangerous level of loudness is reached. This is because teens buy headphones themselves.
Notable Assumptions
The author assumes teens would not buy the headphones that turn off when a dangerous level of loudness is reached.
A
Loud music is most dangerous to hearing when it is played through stereo headphones.
We don’t care when loud music is most dangerous. We need to strengthen the claim that the new line of headphones wouldn’t help stop teen hearing loss.
B
No other cause of hearing loss in teenagers is as damaging as their listening to loud music through stereo headphones.
Like (A), we don’t care how bad loud music is. We need to strengthen the claim that the new line of headphones wouldn’t help stop teen hearing loss.
C
Parents of teenagers generally do not themselves listen to loud music through stereo headphones.
Irrelevant. We care about what the teens are doing.
D
Teenagers who now listen to music at dangerously loud levels choose to do so despite their awareness of the risks involved.
Teens know listening to loud music is bad for their hearing, but they do it anyway. Therefore, they wouldn’t buy a line of headphones that prevents them from this risk by not allowing them to listen to loud music.
E
A few headphone manufacturers already plan to market stereo headphones that automatically turn off when a dangerous level of loudness is reached.
According to the author, those headphones won’t make a difference. We’re trying to strengthen that claim.