Excavations of the Roman city of Sepphoris have uncovered numerous detailed mosaics depicting several readily identifiable animal species: a hare, a partridge, and various Mediterranean fish. Oddly, most of the species represented did not live in the Sepphoris region when these mosaics were created. Since identical motifs appear in mosaics found in other Roman cities, however, the mosaics of Sepphoris were very likely created by traveling artisans from some other part of the Roman Empire.

Which of the following is an assumption on which the argument depends?

A. The Sepphoris mosaics are not composed exclusively of types of stones found naturally in the Sepphoris area.
B. There is no single region to which all the species depicted in the Sepphoris mosaics native
C. No motifs appear in the Sepphoris mosaics that do not also appear in the mosaics of some other Roman city
D. All of the animal figures in the Sepphoris mosaics are readily identifiable as representation of known species
E. There was not a common repertory of mosaic designs with which artisans who lived in various parts of the Roman empire were familiar

from the MGMAT explanation, what they did was reverse the assumption of E. so if they HAD a common repertory of mosaic designs, this would invalidate the entire argument above. Therefore, E. is an essential assumption for the argument presented.
Hope this helps

Assumption questions require that you understand the structure of the argument.
Background: Sepphoris has mosiacs with animals
Premise: Species in the mosiacs didn't live in Sepphoris at the time
Premise: Same species were found in mosiacs in other Roman cities
Conclusion: Therefore, mosiacs were created by traveling artisans.

Assumptions fill the gap between premises and the conclusion. In other words, assumptions are those unstated facts that must be true for the conclusion to be true. The conclusion states that mosiacs were created by TRAVELING artisans, so you would have to assume that the RESIDENT artisans don't have knowledge of these non-resident species.

A. Stones are not relevant to the conclusion
B. This answer doesn't address how knowledge of species only got to Sepphoris from traveling artisans
C. Interesting answer choice, but it could support a traveling artisan conclusion or a common knowledgebase of species across all of Rome
D. This runs counter to the conclusion - if the species are known, then any artisan (not necessarily a traveling artisan) could have created the mosaics
E. This option states that there isn't a common knowledgebase of species, which supports the conclusion that only TRAVELING artisans (those who pick up knowledge of species as they travel throughout Rome) could have created the mosaics

KW
_________________

Kyle Widdison | Manhattan GMAT Instructor | Utah


Manhattan GMAT Discount | Manhattan GMAT Course Reviews | View Instructor Profile

Manhattan GMAT: World-Renowned 99th Percentile Instructors & The Most Comprehensive Curriculum