Last visit was: 23 May 2024, 05:32 It is currently 23 May 2024, 05:32
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Tags:
Show Tags
Hide Tags
VP
VP
Joined: 30 Jan 2016
Posts: 1232
Own Kudos [?]: 4645 [5]
Given Kudos: 128
Send PM
Intern
Intern
Joined: 20 Jun 2014
Posts: 38
Own Kudos [?]: 34 [0]
Given Kudos: 24
GMAT 1: 630 Q49 V27
GMAT 2: 660 Q49 V32
Send PM
Manager
Manager
Joined: 12 Apr 2017
Posts: 109
Own Kudos [?]: 58 [0]
Given Kudos: 33
Location: United States
Concentration: Finance, Operations
GPA: 3.1
Send PM
avatar
Intern
Intern
Joined: 19 Dec 2018
Posts: 34
Own Kudos [?]: 10 [0]
Given Kudos: 0
Send PM
Re: The common ancestors of Australian land- and tree-dwelling kangaroos [#permalink]
D. This statement follows the argument made in the passage that land dwelling kangaroo eventually lost these attributes. Now if modern tree-dwelling kangaroo are descendent of land-dwelling kangaroo, it is obvious that they too won’t have these attributes. Hence, D is the answer.
Manager
Manager
Joined: 22 Apr 2021
Posts: 131
Own Kudos [?]: 11 [0]
Given Kudos: 409
Send PM
Re: The common ancestors of Australian land- and tree-dwelling kangaroos [#permalink]
Hey experts,

KarishmaB GMATNinja AjiteshArun DmitryFarber ExpertsGlobal5

Doubt - I am unable to understand why Option D is correct and why Option A is incorrect. My understanding - Option D goes against fact given in passage that land and tree dwelling kangaroos descended from a common ancestor. We cannot contradict fact hence i rejected this. Option A gives us a reason that why modern kangaroos lack those features i.e. they must back down slowly and opposable thumb where used to descend quickly.

Please help me understand flaws in my reasoning.
Tutor
Joined: 16 Oct 2010
Posts: 14891
Own Kudos [?]: 65439 [1]
Given Kudos: 431
Location: Pune, India
Send PM
Re: The common ancestors of Australian land- and tree-dwelling kangaroos [#permalink]
1
Kudos
Expert Reply
akela wrote:
The common ancestors of Australian land- and tree-dwelling kangaroos had prehensile (grasping) tails and long opposable thumbs, attributes that are well adapted to tree-dwelling but offer kangaroos few advantages on land. It is hardly surprising, therefore, that land-dwelling kangaroos eventually lost these attributes; what is puzzling is the fact that all modern tree-dwelling kangaroos now lack them as well.

Which one of the following, if true, most helps explain the puzzling fact cited above?


(A) Modern tree-dwelling kangaroos must back down tree trunks slowly and carefully, but the common ancestors of modern tree-and land-dwelling kangaroos used their opposable thumbs to descend trees quickly headfirst.

(B) Modern tree-dwelling kangaroos are smaller than most modern land-dwelling kangaroos but larger than their common ancestors.

(C) Modern tree-dwelling kangaroos’ tails cannot grasp branches, but they are somewhat longer and more flexible than those of modern landdwelling kangaroos.

(D) Modern tree-dwelling kangaroos are descended from species of land-dwelling kangaroos that had been land-dwellers for many generations before modern tree-dwelling kangaroos started to develop.

(E) Modern tree-dwelling kangaroos have smaller and weaker hind legs than modern landdwelling kangaroos, and they move more slowly on land than do modern land-dwelling kangaroos.


There were one type of kangaroos long long ago. They had grasping tails and long opposable thumbs which are great for tree dwelling.
From them, split two different types - land dwelling & tree dwelling long long ago.
Then, land dwelling ones lost these two features long ago because they were useless to them.

The odd thing is that the current tree dwellers also do not have these features (though these features would have been useful to them). They would have retained the useful features.
Why don't they have these features?

Option (D) tells us that the modern tree dwelling kangaroos ascended from the land dwellers. So it seems that the old tree dwellers became distinct and the current tree dwellers have evolved from land dwellers only (after the land dwellers lost the two features).
Note that option (D) is not in conflict with the premises. The common ancestors of all kangaroos are the ancient species. They split into two but only land dwellers survived. From the land dwellers, the modern tree dwellers evolved later.
waytowharton

(A) Modern tree-dwelling kangaroos must back down tree trunks slowly and carefully, but the common ancestors of modern tree-and land-dwelling kangaroos used their opposable thumbs to descend trees quickly headfirst.

This is the impact of not having the two features (grasping tails & long opposable thumbs). The modern tree dwellers must back down slowly.
It doesn't explain WHY they don't have the two features.

(B) Modern tree-dwelling kangaroos are smaller than most modern land-dwelling kangaroos but larger than their common ancestors.

Irrelevant.

(C) Modern tree-dwelling kangaroos’ tails cannot grasp branches, but they are somewhat longer and more flexible than those of modern landdwelling kangaroos.

Irrelevant. We need to know why their tails are not grasping tails.

(E) Modern tree-dwelling kangaroos have smaller and weaker hind legs than modern landdwelling kangaroos, and they move more slowly on land than do modern land-dwelling kangaroos.

Irrelevant.

Answer (D)
User avatar
Non-Human User
Joined: 01 Oct 2013
Posts: 17360
Own Kudos [?]: 852 [0]
Given Kudos: 0
Send PM
Re: The common ancestors of Australian land- and tree-dwelling kangaroos [#permalink]
Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: The common ancestors of Australian land- and tree-dwelling kangaroos [#permalink]
Moderators:
GMAT Club Verbal Expert
6936 posts
GMAT Club Verbal Expert
238 posts
CR Forum Moderator
832 posts