Dinosaur tracks show them walking with their feet directly under their

Question

Dinosaur tracks show them walking with their feet directly under their bodies, like  mammals and birds, not extended out to the side in the manner of modern reptiles.

(A) Dinosaur tracks show them walking with their feet directly under their bodies, like

(B) Dinosaur tracks show that they walked with their feet directly under their bodies, as do

(C) Dinosaurs left tracks that showed them walking with their feet directly under their bodies, like

(D) The tracks that dinosaurs left show that they walked with their feet directly under their bodies, as do

(E) In the tracks they left, dinosaurs are shown walking with their feet under their bodies, like

SC19060.02

JOURNAL ARTICLE
 How Dinosaurs Ran 
R. McNeill Alexander
 Scientific American 
Vol. 264, No. 4 (APRIL 1991), pp. 130-137
Published by: Scientific American, a division of Nature America, Inc.
 https://www.jstor.org/stable/24936872 
Page Count: 8

The graph proved to be even more illuminating because it soon occurred to me that I could use it to estimate the speed of dinosaurs from the stride lengths shown by their footprints. Rather surprisingly, great numbers of dinosaur footprints have survived as impressions in mud that turned to stone  . Mossman and William A. S. Sarjeant; SCIENTIFIC AMERICAN, March 1983].  These tracks show that dinosaurs walked with their feet directly under their bodies like  mammals and birds, not sprawled out to either side in the manner of modern reptiles. Consequently, the relation between relative stride length and Froude number for mammals should also apply to dinosaurs. In contrast, estimating dinosaur speed by comparing these giants with modern reptiles would not be appropriate.

GMATNinja · Accepted Answer

The first thing I notice is "them," which has to refer to a plural noun, but there's no plural noun that works here. "Tracks?" Nope. The dinosaur tracks don't show "tracks" walking. A pronoun can be ambiguous, but it cannot be incoherent. So (A) is out.

Same problem as (A), but with "they" instead of "them."

This one fixes the pronoun issue - "them" can refer to "dinosaurs," but now we've got a meaning problem. This version makes it sound as though the tracks literally showed dinosaurs walking, the way, say, a video might show a toddler walking. That would be neat, but it's not terribly logical. The tracks give us information that allows us to see  that  the dinosaurs walked a certain way. But we don't get to see the walking itself.

There's also a problem with the usage of "like" here. Remember, "like" has to compare nouns. What nouns are compared? "Mammals and birds" to "their bodies?" That doesn't make sense. It seems far more logical to compare actions: how dinosaurs  walked  to how mammals and birds  do . When comparing actions, we'd want to use "as," so that's another strike against (C).

This looks okay. We have the plural "dinosaurs" for "they" to refer to. "As" properly compares actions. No other issues are jumping out, let's hang on to this one.

Again, it seems as though the tracks are literally displaying dinosaurs walking. Worse, the dinosaurs appear to be walking  now . And then we've also got "like" illogically comparing "mammals and birds" to their bodies," as opposed to (D), which uses "as" to compare actions.

So (D) it is.

EMPOWERgmatVerbal · Answer

Hello Everyone!

Let's tackle this question, one thing at a time, and narrow down our options quickly so we know how to answer questions like this when they pop up on the GMAT! To begin, let's take a quick look at the question and highlight any major differences between the options in  orange :

Dinosaur tracks show them walking with their feet directly under their bodies, like  mammals and birds, not extended out to the side in the manner of modern reptiles.

(A)  Dinosaur tracks show them walking  with their feet directly under their bodies,  like

(B)  Dinosaur tracks show that they walked  with their feet directly under their bodies,  as do

(C)  Dinosaurs left tracks that showed them walking  with their feet directly under their bodies,  like

(D)  The tracks that dinosaurs left show that they walked  with their feet directly under their bodies,  as do

(E)  In the tracks they left, dinosaurs are shown walking  with their feet under their bodies,  like

After a quick glance over the options, we have 2 main areas we can focus on:

1. How each option begins (Clarity / Verb Tense)
2. like vs. as do (Idioms & Comparisons)

Since #2 is an either/or split, let’s start there because it’ll eliminate 2-3 options rather quickly.  We need to make sure we’re creating a parallel comparison. This sentence is intended to compare  the actions  of dinosaurs walking with  the actions  of mammals and birds walking. Let’s see how each option handles this:

(A) Dinosaur tracks show them walking with their feet directly under their bodies,  like

(B) Dinosaur tracks show that they walked with their feet directly under their bodies,  as do

(C) Dinosaurs left tracks that showed them walking with their feet directly under their bodies,  like

(D) The tracks that dinosaurs left show that they walked with their feet directly under their bodies,  as do

(E) In the tracks they left, dinosaurs are shown walking with their feet under their bodies,  like

We can eliminate options A, C, & E because “like” is only used to compare two things, whereas “as do” is used to compare two actions.  Since we’re supposed to compare the two walking styles, which are actions, we need to stick with “as do.” Now that we have it narrowed down to only 2 options, let’s focus on clarity:

(B)  Dinosaur tracks  show that  they  walked with their feet directly under their bodies, as do 
This is  INCORRECT  because the pronoun “they” is referring back to “dinosaur tracks,” which makes no logical sense. Tracks cannot walk. The pronoun needs a clearer antecedent (dinosaurs, perhaps?).

(D) The tracks that  dinosaurs  left show that  they  walked with their feet directly under their bodies, as do 
This is  CORRECT ! By naming the dinosaurs earlier in the sentence, we can use the pronoun “they” here because it can be clearly attributed to the dinosaur, not the tracks.

There you have it - option D is our winner!  By starting with an easier “either/or” split, we were able to narrow down our options quickly, leaving us more time to focus on more complex issues!

Don’t study for the GMAT. Train for it.

chetan2u · Answer

The main errors..

A) Dinosaur tracks show them walking with their feet directly under their bodies, like 
 'Dinosaur tracks'  seems to be a name of a track rather than showing possession.. Also, the THEIR in  under their bodies  does not modify singular dinosaur and illogically points to tracks. There can be many more appropriate ways to use this phrase.
LIKE shows comparison between NOUNs, and it does not fit in here. We are likely comparing actions by dinosaurs and mammals & birds.

B) Dinosaur tracks show that they walked with their feet directly under their bodies, as do
'as do' is correctly used, but it wrongly compares dinosaur tracks with mammals & birds.
 'Dinosaur tracks'  seems to be a name of a track rather than showing possession.. Also, the THEIR in  under their bodies  and THEY do not modify singular dinosaur and illogically points to tracks.

C) Dinosaurs left tracks that showed them walking with their feet directly under their bodies, like
Clears the pronoun ambiguity, but construction is not proper.
We are  comparing two actions , one by Diosaurs and other by mammals and birds, so LIKE is wrong.

D) The tracks that dinosaurs left show that they walked with their feet directly under their bodies, as do
Pronoun ambiguity is removed in this choice. Also 'as do' is correctly used for comparing two actions. CORRECT

E) In the tracks they left, dinosaurs are shown walking with their feet under their bodies, like
Like is wrong..
Poorly constructed -- In the tracks they left, dinosaurs are shown walking

D

Mandeep1357 · Answer

Dinosaur tracks show them walking with their feet directly under their bodies, like  mammals and birds, not extended out to the side in the manner of modern reptiles.

(A) Dinosaur tracks show them walking with their feet directly under their bodies, like

(B) Dinosaur tracks show that they walked with their feet directly under their bodies, as do

(C) Dinosaurs left tracks that showed them walking with their feet directly under their bodies, like

(D) The tracks that dinosaurs left show that they walked with their feet directly under their bodies, as do

(E) In the tracks they left, dinosaurs are shown walking with their feet under their bodies, like

If we compare first few words and last few words,

In A and B, we have "Dinosaur" and in C, D and E, we have "Dinosaurs", its singular-plural noun error. 
In A, plural pronoun "them" refers to singular noun "Dinosaur"......Eliminate
In B, plural pronoun "they" refers to singular noun "Dinosaur"......Eliminate

If we look at last few words in C, D and E
We have a split of "Like" vs "As"...."Like" is used to compare nouns and "As" is used to compare Actions

Here we are comparing "How dinosaurs walked" with "how mammals and birds walk", we are comparing actions. We need "As" to compare actions. 
Eliminate C and E.

Hence, D is the correct answer.

kumaraaa · Answer

GMATNinja, please address my below query:
While I understand that C is wrong due to meaning issue, I am still not able to get why "Like" can't be used here to compare "Mammals and birds" with "Dinosaur".

ahsanashfaq28 · Answer

not extended out to the side in the manner of modern reptiles

Is extended modifying mammals and birds?

GMATNinja · Answer

If "like" is used to compare dinosaurs to mammals and birds in (C) it would distort the meaning of the sentence.

Think about the intended comparison: the author is trying to say that dinosaurs are similar to mammals/birds in that they all walk with their feet directly under them.

Let's rearrange (C) a bit so that your suggested comparison is more clear:

"Dinosaurs,  like mammals and birds ,  left tracks  that showed them walking with their feet directly under their bodies, not extended out to the side in the manner of modern reptiles."

This DOESN'T say that dinos, mammals, and birds are similar because they walked in the same way. Instead, it says that they are similar because  they all left certain kinds of tracks .

So the use of "like" isn't quite right in (C).

(D), on the other hand, very clearly compares how dinos walk with how mammals/birds walk.

I hope that helps!

GMATNinja · Answer

Mammals and birds  themselves  can't really be "extended" (unless something very strange is going on), so we know that "extended" doesn't modify mammals and birds.

Instead, the author is trying to describe the position of the  feet  of various animals.

The feet of dinosaurs were "directly under their bodies," while the feet of modern reptiles are "extended out to the side."

So, "extended" is just describing the position of reptiles' feet when they walk.

I hope that helps!

Rasalghul853 · Answer

But is D parallel? A show X not Y. Here X and Y are not parallel. Please rectify where I have gone wrong.

egmat · Answer

But is D parallel? A show X not Y. Here X and Y are not parallel. Please rectify where I have gone wrong. Hello Rasalghul853 , I will be glad to help you with this one.

Choice D is perfectly parallel in the comparison that it presents. The sentence intends to compare dinosaurs with mammals and birds. Why these entities have been compared? They have been compared because they all walked or walk with their feet under their bodies, not extended out to the side in the manner of modern reptiles. This is common in all t these entities, not only in dinosaurs. This is the intended logical meaning. From the grammatical standpoint, there is no parallelism in "A show X not Y". There is no parallelism marker here, so there is no list here. Hope this helps.

Thanks. Shraddha

nikitamaheshwari · Answer

Can "do" in Option choice D refer to "walked". How can do refer to past tense walked here?

kittle · Answer

Hey GMATNinja - don't you think that in choices C and E, the comparison is between "dinosaurs" and "birds and mammals" as when separated using a comma, the like compares what follows it with the subject of the sentence. Eg: Natural satellites do not have light of their own, like the planets. In this sentence, noun entities are compared.

GMATNinja · Answer

That sample sentence is a good example of a construction that might not be definitively wrong, but creates a problematic meaning.

If you wrote, "Natural satellites, like the planets, do not generate their own light," it would be crystal clear that you were comparing the satellites to the planets and that both do not generate their own light.

But in that sample version, it sounds as though the "planets" might be compared to the "light" itself, meaning that satellites don't create planet-like light. Can a reader eventually figure out what's intended? Maybe. But the GMAT would likely frown on the confusion or illogical meaning.

Also, even if you didn't treat the usage of "like" as a definitive error in (C) and (E), each of those options has another logical problem. All you need is one concrete error to get rid of an option, so there'd be no need to agonize over the "like."

I hope that clears things up a bit!

sid0791 · Answer

Hi  GMATNinja

In D, doesn't it seem like, that Dinasours purposefully left the tracks?

GMATNinja · Answer

Nah. If a thief leaves behind fingerprints we wouldn't think he'd done so intentionally. Same thing if an animal leaves behind tracks. Living things leave traces of their presence. No reason to believe it's intentional. (If the phrase had been, "Dinosaurs left tracks  to  show," then you'd have an argument. But that's not what we have.)

I hope that clears things up!

Rickooreo · Answer

egmat   KarishmaB   GMATNinja   EMPOWERgmatVerbal

In Option D - that dinosaurs left - this is a relative clause which we eliminate while analysing sentence, so the sentence will look like
 The tracks  that dinosaurs left  show that they walked  with their feet directly under their bodies, as do

Implying that tracks show that tracks walked?

Another way to look at this can be they can refer to either tracks or dinosaurs. The subject of option D is tracks and hence it is referring to tracks

ExpertsGlobal5 · Answer

Hello  Rickooreo ,

We hope this finds you well.

To answer your query, Option D does not imply that the tracks walked; remember, pronoun ambiguity is only a concern if there are multiple nouns that the pronoun can  logically  refer to.

To understand the concept of "Exception to Pronoun Ambiguity" on GMAT, you may want to watch the following video (~1 minute):

https://www.youtube.com/watch?v=mkYO2EmB7Vo

All the best!
Experts' Global Team

AashishGautam · Answer

GMATNinja   egmat   karishma

I have a doubt regarding the modification in D.

The tracks that dinosaurs left show that they walked with their feet directly under their bodies, as do mammals and birds, not extended out to the side in the manner of modern reptiles.

Here, extended should modify the noun feet. However, to do so, it has to cross over the verb do. Is this allowed as per grammar rules?

ExpertsGlobal5 · Answer

Hello  AashishGautam ,

We hope this finds you well.

To answer your query, here "extended out to the side" does modify "feet".

"extended out to the side" and "directly under their bodies" are two parallel noun modifiers that both act upon the noun "feet", which is a part of the adverbial phrase "with their feet", which in turn modifies the verb "walked".

We hope this helps.
All the best!
Experts' Global Team

Dinosaur tracks show them walking with their feet directly under their

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 Sentence Correction (SC - EA only) Questions

Dinosaur tracks show them walking with their feet directly under their

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