V39-21

Question

Paleontologist: Fossil evidence suggests that the crest of the dinosaur  Parasaurolophus  contained hollow tubes connected to its nasal passages. One researcher has proposed that the dinosaur used this crest to produce loud, resonant calls for long-distance communication. However, this hypothesis is implausible, since any such call would have had to exceed 100 decibels to travel the distances proposed, and the structure of the crest does not appear capable of producing such high-volume sound.
 
Which of the following, if true, would most effectively rebut the paleontologist’s objection?

A.  Parasaurolophus  likely traveled in herds, where long-distance calls may have had limited usefulness.
B. Similar hollow-crest structures are found in many other herbivorous dinosaur species.
C. Fossil reconstructions of the  Parasaurolophus  crest suggest it was reinforced with cartilage, making it slightly more rigid than bone alone.
D. The crest may have served multiple functions, including both sound production and thermoregulation.
E. Soft-tissue structures that do not fossilize could have been involved in vocalization in  Parasaurolophus .

Bunuel · Answer

Official Solution:

Paleontologist: Fossil evidence suggests that the crest of the dinosaur  Parasaurolophus  contained hollow tubes connected to its nasal passages. One researcher has proposed that the dinosaur used this crest to produce loud, resonant calls for long-distance communication. However, this hypothesis is implausible, since any such call would have had to exceed 100 decibels to travel the distances proposed, and the structure of the crest does not appear capable of producing such high-volume sound.
 
Which of the following, if true, would most effectively rebut the paleontologist’s objection?

A.  Parasaurolophus  likely traveled in herds, where long-distance calls may have had limited usefulness.
B. Similar hollow-crest structures are found in many other herbivorous dinosaur species.
C. Fossil reconstructions of the  Parasaurolophus  crest suggest it was reinforced with cartilage, making it slightly more rigid than bone alone.
D. The crest may have served multiple functions, including both sound production and thermoregulation.
E. Soft-tissue structures that do not fossilize could have been involved in vocalization in  Parasaurolophus .

Correct Answer: (E) 
 
The paleontologist argues that  Parasaurolophus  could not have used its crest to produce long-distance calls because the crest’s structure alone does not appear capable of generating the required volume. Choice (E) effectively rebuts this objection by introducing the possibility that soft-tissue structures—which do not fossilize—may have contributed to vocalization. If such structures were involved, the crest’s apparent limitations may not reflect the dinosaur’s full sound-producing capacity. Thus, the objection based solely on fossilized bone structure is weakened.
 
 Incorrect Options: 
 
(A) Suggests that long-distance calls may not have been useful due to herding behavior. However, this challenges the purpose of the calls, not the feasibility of producing them, and therefore does not address the paleontologist’s objection.
 
(B) Notes that other species had similar crests but does not provide evidence that those crests could produce the required volume. This background detail neither supports nor refutes the argument in question.
 
(C) Describes the crest as reinforced with cartilage, but cartilage alone is unlikely to produce or amplify sound significantly. This choice does not effectively counter the volume-based objection.
 
(D) States that the crest may have served multiple functions. While this may be true, it does not address whether the crest could have produced loud calls, and therefore does not rebut the specific objection raised.

Answer: E

Sushi_545 · Answer

if  cartilage alone is unlikely to produce or amplify sound significantly. This choice does not effectively counter the volume-based objection then
 how does " Soft-tissue structures that do not fossilize could have been involved in vocalization in  Parasaurolophus" does?

poor quality question.

hr1212 · Answer

Hi Sushi_545 ,

If I understand correctly, I think you are talking about options C and E.

There’s a minor difference b/w them. One option focuses on improving the bone rigidity which might have nothing do with vocalisation whereas other is explicitly describing elements which would have helped in vocalisation but would not have fossilised. Focusing on the exact wording would help you identify such subtle differences and eliminate trap choices.

findingmyself · Answer

Hi @sushi_545

In weaken the argument questions , we essentially needs to cast doubt on the claim made, doesn't have to be a must be true scenario, In this case here:

Soft tissue structures that donot fossilize could have been involved in vocalization in Parasaurolophus   
   Imagine if for eg, there were soft tissues say like air sacs or anything like an amplifier, that didn't fossilize for some reason, they could have amplified sound, helping the dinosar exceed 100 db. This is directly introduces reasonable doubt on the paleontologist's argument.

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