IanStewart wrote:
homersimpsons wrote:
Triumba birds reside in the polar regions and need to migrate to warmer areas in winters since winters in the polar regions are not conducive to the survival of the birds. In recent years, because of some unanticipated genetic changes, the flying capability of the birds has been declining and is expected to continue do so in the future.
Which of the following statements is best supported by the passage above?
B)If Triumba birds don’t develop measures to counter adversarial genetic changes, they face a likelihood of extinction.
D)Unless Triumba birds develop an ability to live in the polar regions during winter, they will be extinct in some time.
I found this question kind of funny - the birds are affected by "unanticipated genetic changes". Unanticipated by whom? The birds? I can't guess what that word is doing there. Then answer B misuses "adversarial" (they mean "adverse", which means something very different).
There's no good answer here. It's not precisely clear to me what birds can do to "counter adversarial genetic changes" (the birds can't become genetic engineers). But even if we interpret B to mean "unless the birds find a way to compensate for their diminished flight", it's still not a great answer. It would be a better answer if D wasn't there, but then D would be a good answer if B wasn't there. Answer D suggests it's possible that the birds can adapt to polar winters. Answer B suggests that it's possible that the birds can "counter genetic changes". If both of those things are possible, then neither B nor D alone can possibly be a valid inference, because the birds still have a way to survive even if they can't do the thing mentioned in each answer choice. They're not valid inferences anyway, because we have no information about the extent to which the birds' flight is affected by the genetic changes. Maybe they're worse at flying, but are still perfectly capable of flying well enough to migrate in the winter.
So I don't think there's any reason to pay attention to this question. What is the source?
I feel the option E to be better than all others. The reasoning is below-
Triumba birds migrate to warmer areas in winters because winter is not conducive for survival of birds (all species of birds, not just Triumba birds).
"It indicates that the author is talking about all species of birds, not just Triumba."
Further, statement on reduced flying capacity is made for birds (all species together), and not specifically for Triumba birds.
The reasoning might be, that triumba birds might be still having same capacity and are unaffected since it is a need and habit to fly for long distances. Probability is, that some other species has shown different behaviour, resulting overall birds' average declined capability.
This leads to the probable explanation that there are some birds who do not migrate (as in option E) but have good enough flying capability. Since they don't need higher flying capability naturally, it is incurring a genetic change in that particular species (Darwin's evolution theory) and hence overall average capability is reducing.