"Surprising" Phenomenon
Mosquito-borne disease outbreaks typically increase after extended periods of wet weather, but in areas where mosquitoes breed primarily in wetland habitats, there tend to be more outbreaks after droughts.
Objective
The right answer will be a hypothesis that describes a key difference between areas where mosquitoes breed primarily in wetland habitats and areas where mosquitoes breed primarily in other types of environments. That difference must explain why droughts create improved conditions for mosquito-borne disease in areas where breeding occurs in wetland habitats. This difference might relate to humans’ susceptibility to disease, mosquitoes’ disease carriage abilities, or mosquito birthrates under drought conditions in these areas.
A
The use of insecticides is typically prohibited in wetland habitats.
This has nothing to do with droughts or wet periods—presumably, insecticides are prohibited regardless of weather conditions, so (A) doesn’t help explain the increased disease outbreaks that follow droughts in wetland habitats.
B
Human populations tend to be sparse in areas near wetland habitats.
This has nothing to do with droughts or wet periods, so it doesn’t help explain the increased disease outbreaks that follow droughts in wetland habitats.
C
Wetland habitats contain numerous aquatic insects that prey on mosquito larvae.
If wetland habitats contain aquatic insects that eat mosquito larvae, it makes sense that periods of drought lead to more cases of mosquito-borne disease. These aquatic predators die or are weakend during droughts, allowing more larvae to hatch and grow into diseased mosquitoes.
D
Wetland habitats host a wider variety of mosquito species than do other areas where mosquitoes breed.
This has nothing to do with droughts or wet periods, so it doesn’t help explain the increased disease outbreaks that follow droughts in wetland habitats.
E
Periods of drought in wetland habitats create conditions conducive to the emergence of new plant growth.
We have no information about how new plant growth might or might not impact incidences of mosquito-borne disease, so this answer choice doesn’t help resolve the discrepancy at hand.
Summarize Argument: Counter-Position
The executive concludes that critics are wrong about her communications devices being dangerously distracting. She supports this by saying that drivers who want to use communications devices will do so regardless, and that these devices are safer because they are easier to use.
Identify and Describe Flaw
The executive makes the unwarranted assumption that the devices are safer just because they're easier to use. But even if they are safer than other devices, she still doesn't address the critics' concern that they are dangerously distracting, nor does she give any reason to believe that they are not dangerously distracting. The fact that they're easier to use and that drivers will use them anyway doesn't change the fact that they might still be dangerously distracting.
A
attempts to apply a general principle to a situation to which that principle is not applicable
The executive doesn’t attempt to apply any principle at all. She also doesn’t wrongly apply a generalization to a specific situation. Instead, she draws a conclusion about the communications devices based on premises that are also about the communications devices.
B
fails to address the substantive point of the criticism that it is responding to
The executive fails to address the critics’ main point: that the communications devices are dangerously distracting. Just because they're easier to use and drivers will use them anyway doesn't change the fact that they might still be dangerously distracting.
C
treats a condition that is necessary to establish its conclusion as one that is sufficient to establish that conclusion
This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The executive doesn’t make this mistake; her argument doesn’t rely on conditional logic. Instead, she counters the critics’ position without actually addressing their criticism.
D
presumes, without providing justification, that all communications devices are the same with respect to driver distraction
Actually, the executive explicitly claims that her communications devices are safer with respect to driver distraction. She doesn’t assume that all devices are the same.
E
is based on premises that presume the truth of the argument’s conclusion
This is the cookie-cutter flaw of circular reasoning. The executive doesn’t make this mistake. Her premises may not support her conclusion well, but they are distinct from her conclusion.
Olson: Given that the oldest primate fossils discovered so far date back only 55 million years, your estimate of how long primate species’ development has gone on is sheer speculation.
Speaker 1 Summary
Carrillo argues his statistical model shows that the first primates developed 81.5 million years ago.
Speaker 2 Summary
Olson believes that Carillo’s estimate is purely speculative because the oldest primate fossils found date back to 55 million years ago.
Objective
Disagreement: Carillo and Olsen disagree over whether Carillo’s model is accurate.
A
primates have been around for more than 55 million years
Carrillo agrees with this because he believes that the first primate developed around 81.5 million years ago. However, Olsen also agrees! He says that the oldest fossil dates back 55 million years, implying that the first primate was older than 55 million years old
B
Carrillo’s statistical model is a reliable way of dating the first appearance of primate species
Carrillo certainly agrees that his model is correct. Olson directly states that Carrillo's model is based on “pure speculation,” making it unreliable.
C
the available sample of primate fossils is representative of the variety of primate species that have existed
This answer choice is far too broad for either speaker to have a position on. Olson only discusses *one* fossil, while Carrillo is primarily focused on the results of his model. You have to make a lot of assumptions to make this work.
D
the dating of the primate fossils that Olson cites is accurate
Olson certainly agrees that his citation is correct. However, Carillo does not challenge or address this at all. Carillo’s discovery and Olson’s citation could both be correct. It is possible that the earliest primate fossil has never been discovered.
E
fossils of the first primate species that developed have been discovered
Carrillo does not address this statement at all, and it is implied that Olson disagrees. He acknowledges that the oldest fossils discovered “so far” date back 55 million years. He likely believes that there could be older fossils that have yet to be discovered.