Many marine organisms defend themselves from predators, using a dark

Question

Many marine organisms defend themselves from predators, using a dark ink-like pigment secreted from an inch-long sac attached to their epidermis. A fossil from the Jurassic period, dated at almost 155 million years old and discovered in the Wiltshire region, contains a perfectly-preserved ink-sac that was probably from a now-extinct species of squid, the Belemnotheutis Antiquus, whose exact origins had not been previously established. Therefore, this form of self-preservation in marine organisms is at least 155 million years old.

Which of the following, if true, most strengthens the conclusion above?

(A) Ink-sacs in marine organisms have functions other than self-preservation.

(B) The Belemnotheutis Antiquus had physiological features that exist only as inactive organs in some present-day species of squid.

(C) Marine organisms other than squids also have epidermal ink-sacs that the organisms use to ward off predators.

(D) Fossils found in the Wiltshire region have previously provided evidence that land-based organisms from the Jurassic period had epidermal organs with the function of self-preservation.

(E) Remains of a squid belonging to the Belemnotheutis Antiquus family were also found in the Wiltshire region and estimated to be from the Jurassic period

rsama · Answer

A, B, C, and D all are irrelevant to conclusion made in argument. Thus POE confirms E.

Mavisdu1017 · Answer

Yes same here. But honestly I feel E is bullshit and nonsense, how does it strengthen the argument? Just seems to repeat the fossil...
Anybody can explain?

RenB · Answer

Hi,
I'll try to explain my logic-
The argument talks only about an ink-sac, that was 'probably' a squid's. The conclusion gives a generalisation that marine animals would have had ink sacs but nowhere does the argument 'confirm' that the ink-sac belonged to a marine animal.
Option E mentions that a squid's remains were also found around the same area and these remains appear to be from the Jurassic period. This further strengthens my belief that the ink-sac found was of the squid that is estimated to be from the J period so yes, I can conclude with more confidence that this ink sac phenom is at least 155 years old (from the J period).

Yudhajit22 · Answer

I think the conclusion is more about the time for which this kind of self preservation exists i.e , for 155 M years.

Only E provides some sort of support to that and hence strengthens.

RenanBragion · Answer

(A) Ink-sacs in marine organisms have functions other than self-preservatio -  weakens the argument because if these organisms were used for other functions c maybe they weren’t used back then for self preservation

(B) The Belemnotheutis Antiquus had physiological features that exist only as inactive organs in some present-day species of squid. -  irrelevant, the fact that some physiological features from back then are inactive today does not directly support the claim that the organs were used for self-preservation back then

(C) Marine organisms other than squids also have epidermal ink-sacs that the organisms use to ward off predators.-  irrelevant again

(D) Fossils found in the Wiltshire region have previously provided evidence that land-based organisms from the Jurassic period had epidermal organs with the function of self-preservation. -  irrelevant because the argument calls out specifically that the organs were used for self preservation by marine animals, so whatever happens on land does not support the argument directly

(E) Remains of a squid belonging to the Belemnotheutis Antiquus family were also found in the Wiltshire region and estimated to be from the Jurassic period -  this helps triangulate that the fossils were indeed from that time period. I personally find it a weak support, but support nonetheless

Many marine organisms defend themselves from predators, using a dark

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Many marine organisms defend themselves from predators, using a dark

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards