Summarize Argument: Counter-Position
The author argues that stage directions in operas can be reflected in their music. In support, we get an example: Mozart began some opera scenes with music that sounded like the squeaking of changing scenery. This establishes the sub-conclusion that Mozart intended the music to sound like the stage direction to change scenery, which leads to another sub-conclusion that at least one stage direction can be reflected in music. The author uses this to conclude that other stage directions can also be reflected.
Identify Argument Part
The statement about scenes in Mozart’s operas opening with music that sounds like the squeaking of changing scenery supports both of the sub-conclusions (Mozart’s intention and music reflecting a stage direction), and through them the main conclusion (music can reflect several stage directions).
A
a change of scenery is the stage direction most frequently reflected in an opera’s music
The statement about Mozart opening scenes with squeaky music does not support the claim that scenery changes are the most frequent stage direction, it’s unrelated. The latter claim isn’t supported by anything, it’s just stated as a fact.
B
an opera’s stage directions are never reflected in its music
Nothing in the argument supports the claim that stage directions are never reflected in opera music. That’s the claim the critics make, and the author’s goal is to prove them wrong.
C
an opera’s music can have an effect on the opera’s stage directions
The author never claims that an opera’s music can impact the stage directions. There’s no indication that the music can change what the stage directions are or how they’re carried out.
D
a variety of stage directions can be reflected in an opera’s music
This is the main conclusion, and it is supported by the claim statement about Mozart opening scenes with squeaky music. The support is offered through a chain of sub-conclusions.
E
the most frequent relation between an opera’s music and its stage directions is one of musical imitation of the sounds that occur when a direction is carried out
The author never claims that this is the most frequent relationship between music and stage directions. It’s offered as a single example, but that doesn’t mean there aren’t others.
Summary
Sea sponges live on the ocean floor and feed by filtering water. Two sponge types (tubular sponges and vase-shaped sponges) can filter feed without help from the current, so they do well in quiet waters. They also can’t live in stronger currents, because they would be dislodged from the ocean floor. Finally, both tubular and vase-shaped sponges were widespread in the late Jurassic period.
Strongly Supported Conclusions
These facts strongly support the conclusion that the late Jurassic period had many areas of ocean floor with slow currents, thus allowing tubular and vase-shaped sponges to be widespread. They also support the conclusion that areas with slow currents can still have enough fresh water moving through for sponges to find food.
A
Few tubular or vase-shaped sponges lived before the late Jurassic period.
Like (B), this is not supported. The only period covered by the stimulus is the late Jurassic: we don’t know what conditions were like for sponges, or how many sponges were around, either before or after.
B
Tubular and vase-shaped sponges were more common during the late Jurassic period than in succeeding geological eras.
Like (A), this is not supported. Because the facts only apply to the late Jurassic period, we can’t draw any conclusions about other periods, either before or after.
C
During the late Jurassic period there were many areas of the ocean floor where currents were weak.
This is strongly supported. The facts tell us that tubular and vase-shaped sponges can only live on the ocean floor where the current is weak. So, for them to be widespread during the late Jurassic period, there had to be widespread areas of the ocean floor with weak currents.
D
All sponges that are neither tubular nor vase-shaped inhabit areas of the ocean floor where there are extremely strong currents.
This is not supported. The author only discusses tubular and vase-shaped sponges; we learn nothing about other kinds of sponges. We don’t even know if there are other sponges, let alone what environmental conditions they prefer.
E
No types of sponge live in large colonies, since sponges do not flourish in areas where much of the water has been filtered by other sponges.
This is not supported. The stimulus doesn’t directly discuss sponge colonies, and we also cannot infer this from what we do know. We just don’t have enough detail about sponges’ filter feeding to know whether a sponge in a colony could still access enough food to flourish.
Summarize Argument: Counter-Position
The author claims that different species commonly change their environment in ways that aid their survival, contrary to the assumption that only very intelligent species do so. To support this claim, the author gives an example of plankton, whose gas emissions lead to clouds forming over the ocean, which cools the Earth and benefits the plankton.
Identify Conclusion
The conclusion is the author’s broad statement that the characteristic of species altering their environment to assist their own survival “is actually quite common.”
A
The Earth would be far warmer than it is now if certain species of plankton became extinct.
This may be implied by the statements in the argument, but it is not the main conclusion because plankton are only used as an example to support the more general claim that many species beneficially alter their environments.
B
By altering their environment in ways that improve their chances of survival, certain species of plankton benefit the Earth as a whole.
The author never makes a claim that the plankton’s effects on the environment benefit the Earth as a whole. This is easy to assume based on knowledge that global warming is harmful, but it is not something the author says.
C
Improving their own chances of survival by altering the environment is not limited to the most highly evolved species.
This accurately captures the author’s main conclusion. The rest of the argument, i.e. the plankton example, provides support for the author’s claim that beneficial environment alteration is common and not restricted to highly-evolved species.
D
The extent of the cloud cover over the oceans is largely determined by the quantity of plankton in those oceans.
This is not something the author claims. Based on the argument, plankton might be sufficient to emit particles that cause cloud cover, but we don’t know if they’re necessary or if there may be other sources of these particles.
E
Species such as plankton alter the environment in ways that are less detrimental to the well-being of other species than are the alterations to the environment made by more highly evolved species.
The author never says anything about how other species are affected by the changes plankton make. The focus is on one species at a time, not the wider effects.