A should be for correct comparison.

sam2304 wrote:Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes form a random pattern.

A. Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes
B. Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that
C. Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds' tubes
D. Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds
E. Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes

Please explain your choice.

IMO: A as well, but is usage of whereas correct?

sam2304 wrote:Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes form a random pattern.
A. Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes
B. Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that
C. Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds' tubes
D. Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds
E. Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes

Please explain your choice.

Inappropriate comparison btn MAMMALS and TUBES in C & D - drop them
E - its would have been better to have THE TUBES after comma to make the comparison btn TINY TUBES...TUBES clear; WHICH could refer to BONE CELLS, making the meaning non-sensical
B - apart of the issue of not placing TINY TUBES and TUBES in parallel position, the 2nd clause BIRDS HAVE TUBES...convey a state while the first clause (TINY TUBES..ARE ARRAYED) convey an action; Use of THAT ARE ...makes the sentence wordier as well

IMO A
The use of WHEREAS...makes it as a dependent clause (just as THOUGH/ALTHOUGH)

Hello Everyone!

This is a great example of a comparison question you might find on the GMAT! Let's start by taking a closer look at the original question and highlight any major differences we can find in orange:

Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes form a random pattern.

(A) Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes
(B) Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that
(C) Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds' tubes
(D) Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds
(E) Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes

We already know that this is a comparison question, so we don't need to start with the obvious differences. Instead, let's look at the most common grammar rule that's tied to comparisons: PARALLELISM!

Whenever we see comparison questions, the first thing we should look at is if the two items being compared to one another are parallel. They need to be the same type of thing, worded similarly, and in the same number. Let's check out each option to see which comparisons are parallel, and eliminate the ones that are not:

(A) Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes --> PARALLEL
(B) Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that --> NOT PARALLEL
(C) Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds' tubes --> NOT PARALLEL
(D) Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds --> NOT PARALLEL
(E) Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes --> NOT PARALLEL


There you have it - only option A compares two parallel items! If you can become familiar with the common problems with certain types of sentences (lists, comparisons, hypotheticals, etc.), finding the right choice is much easier!


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

Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes form a random pattern.


(A) Whereas in mammals the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, in birds the tubes
This is correct answer choice.

(B) Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed in mammals in parallel lines, birds have tubes that
Whereas tube in mammals in parallel lines, birds tubes that – incorrect and not parallel

(C) Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are arrayed in parallel lines, birds’ tubes
Unline mammals, bird’s tubes – mammals is compared to tubes

(D) Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are arrayed in parallel lines, the tubes in birds
Unline mammals, tubes in birds – mammals is compared to tubes

(E) Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are arrayed in parallel lines, in birds the tubes
Unlike the tiny tubes, in birds the tubes. – tiny tubes is compared to birds