- PowerScore Staff
- Posts: 8950
- Joined: Feb 02, 2011
- Wed May 01, 2013 11:00 pm
#35644
Complete Question Explanation
Must Be True—PR. The correct answer choice is (E)
This stimulus presents us with two facts regarding male Trinidadian guppies: first, males with
large spots are more attractive to females and thus more likely to mate than those with small spots.
Second, males with large spots are also more attractive to predators and more likely to be eaten than
those with small spots. Therefore, an advantageous future in most conditions can be disadvantageous
in waters where predators are abundant. Note that the stimulus does not contain a conclusion, which
may be provided in the correct answer choice. Since the question stem indicates that each of the
answers is a generalization, try to substitute specific words or phrases from the stimulus into each
answer choice wherever possible. If the answer choice contains elements that are missing from the
stimulus, cross it out.
Answer choice (A): Large spots is obviously a trait that helps attract mates, but we cannot determine
if this trait is more dangerous to either sex because we don’t know if females ever have spots, let
alone large spots. This is a Half-Right, Half-Wrong answer.
Answer choice (B): The stimulus discusses attractiveness and mating opportunities, but never
addresses number of offspring. We cannot conclude which organisms will have the greatest number
of offspring from the stimulus. Don’t allow the testmakers to conflate similar but not identical
concepts such as mating opportunities and possibly resulting offspring.
Answer choice (C): As with answer choice (B), this answer is incorrect because it discusses number
of offspring. Guppies with small spots will survive longer than those with large spots in the presence
of predators, but simply surviving does not ensure that they will have the greatest number of
offspring and the large-spotted guppies may generally outlive small-spotted guppies when predators
are not abundant.
Answer choice (D): This answer is similar to answer choice (A). The only trait discussed in the
stimulus is the size of spots and we are told that both large and small spots can be harmful to male
guppies, but we have no comparable information for female guppies.
Answer choice (E): This is the correct answer choice. As discussed above, having large spots may
increase a guppy’s opportunities for mating, but being eaten by a predator will surely decrease them.
Where predators are abundant, only small guppies will have any opportunities to mate.
Must Be True—PR. The correct answer choice is (E)
This stimulus presents us with two facts regarding male Trinidadian guppies: first, males with
large spots are more attractive to females and thus more likely to mate than those with small spots.
Second, males with large spots are also more attractive to predators and more likely to be eaten than
those with small spots. Therefore, an advantageous future in most conditions can be disadvantageous
in waters where predators are abundant. Note that the stimulus does not contain a conclusion, which
may be provided in the correct answer choice. Since the question stem indicates that each of the
answers is a generalization, try to substitute specific words or phrases from the stimulus into each
answer choice wherever possible. If the answer choice contains elements that are missing from the
stimulus, cross it out.
Answer choice (A): Large spots is obviously a trait that helps attract mates, but we cannot determine
if this trait is more dangerous to either sex because we don’t know if females ever have spots, let
alone large spots. This is a Half-Right, Half-Wrong answer.
Answer choice (B): The stimulus discusses attractiveness and mating opportunities, but never
addresses number of offspring. We cannot conclude which organisms will have the greatest number
of offspring from the stimulus. Don’t allow the testmakers to conflate similar but not identical
concepts such as mating opportunities and possibly resulting offspring.
Answer choice (C): As with answer choice (B), this answer is incorrect because it discusses number
of offspring. Guppies with small spots will survive longer than those with large spots in the presence
of predators, but simply surviving does not ensure that they will have the greatest number of
offspring and the large-spotted guppies may generally outlive small-spotted guppies when predators
are not abundant.
Answer choice (D): This answer is similar to answer choice (A). The only trait discussed in the
stimulus is the size of spots and we are told that both large and small spots can be harmful to male
guppies, but we have no comparable information for female guppies.
Answer choice (E): This is the correct answer choice. As discussed above, having large spots may
increase a guppy’s opportunities for mating, but being eaten by a predator will surely decrease them.
Where predators are abundant, only small guppies will have any opportunities to mate.