The dinosaurs in the late cretaceous period failed to survive on the p

Had there been an "and" between the two examples "inadequate food supplies" and "harsh weather", your logic would've made perfect sense. But because it isn't and the two examples do not refer directly to the dinosaurs, the same should be true for the third example - an inability to....


IMO, the answer is A.

Any solid reasons for elimination of choice E?

"Lacking an ability" does not clearly tell you who lacks the particular ability and is not parallel with the first two factors since it can refer directly to the dinosaurs while the first two do not. The correct usage of E would have been - "their lack of an ability".

I think A should be right becoz when an articles like a,an,the is followed its a noun
Here in A An inabiity which is a noun and all the factors which are parallel are also noun..

So now leaning towards A

The inability is referring to the factor, so IMO
A should be the answer

I think its A.

The question ends with a list of factors A,B and C. Each of these factors is a noun preceded by an adjective ( noun phrase ) - inadequate food supplies, harsh weather and ....

The dinosaurs in the late cretaceous period failed to survive on the planet because of factors such as inadequate food supplies, harsh weather, and an inability to adapt to the changing environment.

A) an inability - It is a noun phrase which fits this sentence.
B) that they were unable - It is not parallel to the sentence structure.
C) because they were unable - parallelism breaks.
D) being unable - being unable is not correct. being seems to refer to present tense. The sentence already says that they failed to survive.
E) Lacking an ability - wordy, inability seems better.

Somebody failed something because of factors such as: noun, noun, and noun.

A) an inability
Noun. Correct.
B) that they were unable
Not parallel.
C) because they were unable
Not parallel.
D) being unable
If: because of + being unable -> then correct. But we have: because of factors such as: being unable -> not parallel to the nouns in the list.
E) Lacking an ability
Gerund is noun but worse parallel to simple nouns in the list.

If option E is stated as "The lacking an ability will that be right?

As I wrote

use of "the"makes it a noun i guess ,which should be perfectly parallel?please correct me if this is wrong!! thanks in advance

since the underlined portion is not covering "and" that means all factors mentioned constitute one single list . Therefore to maintain parallelism within all factors A option is best . E option is a verb , D option being is wrong ...that and because also break parallelism .

Hence Answer should be A .

Nice explanation guys, updated the post with OA and OE

The dinosaurs in the late cretaceous period failed to survive on the planet because of factors such as inadequate food supplies, harsh weather, and an inability to adapt to the changing environment.

(A) an inability

CORRECT. The sentence contains a list of factors that kept the dinosaurs from surviving on Earth: "inadequate food supplies, harsh weather, and an inability to adapt to the changing environment." In lists of examples, all the examples must be parallel (in the same form). The list has, as its elements, nouns, which are parallel. Thus, this choice contains no error. If you understand the list, this is a pretty straightforward parallelism question.

(B) that they were unable

This choice a clause "that they were unable to communicate with Native Americans" is a part of the list instead of a noun, thus violating the parallelism.

(C) because they were unable

As in (B) this choice is incorrect because "and because they were unable to adapt …." is a clause rather than a noun, thus violating the parallelism.

(D) being unable

This choice is incorrect because "and being unable to ….." is a verb construction rather than a noun, thus violating the parallelism.

(E) Lacking an ability

This choice is incorrect because "and lacking ability to …." is a verb construction rather than a noun, thus violating the parallelism.

zhanbo - could you please help me understand why in Option E "lacking" is not a "noun" acting as a gerund? The explanation says that "lacking an ability" is a verb, but I am not able to completely grasp why it is not a noun.
I often get confused in parallelism questions involving noun, gerund and '-ing' verbs.

Pankaj0901, I agree with you that gerunds function as a noun. Gerunds are more like ad-hoc nouns. If they are used more frequently, many dictionaries will eventually treat them as nouns. For example: financing, funding, making, and recycling are all standard dictionary entries as proper nouns.

There is actually an entry for "lacking" in many dictionaries as well, not as a noun but as an adjective.

So, gerunds are ad-hoc, or second-class, nouns. For the purpose of parallelism when other items (of a list) are proper nouns, the best answer had better also furnish a proper / first-class noun. For parallelism, the closer the match, the better.

Besides, we find an additional merit in (A): shorter is better. (E) uses more words with no additional benefits.

Ultimately, I think that test makers justify their answers by pointing out that this option is preferred by most reputable essayists. (E) does sound a bit abrupt. But we test takers may not have the acute appreciation of test makers. By insisting on close parallelism (with a bias in favor of economical construction), we should be able to deal with this question just fine.

Thank you zhanbo.