Pack 5 Q2: Cacti, like other drought tolerant plants...

Cacti, like other drought-tolerant plants, can survive with little rain because of having the ability of retaining moisture through modified structures, such as spines and thick stems; however, when there is rain, their wide, shallow root systems allow them to absorb water quickly throughout a large area.

Able to do something is idiomatically better than able of -ing form. So, narrow down to B,C and D. C has pronoun reference error, their can refer to cacti or other plants. Besides, option C and D also distort the meaning of original sentence by removing cause-effect relationship. So, incorrect.

A. rain because of having the ability of retaining - Idiomatically incorrect
B. rain because they are able to retain - Seems no error, hold it.
C. rain, in their ability to retain - Pronoun reference error and this option distorts the meaning also by removing the cause-effect relation of original sentence.
D. rain, having their ability to retain - This option distorts the meaning also by removing the cause-effect relation of original sentence.
E. rain, due to having the ability of retaining - Idiomatically incorrect

Imo. B

One may read the second clause of the sentence that goes after the semicolon and notice that the sentence uses Present tense:

Cacti [blah-blah] can survive with little rain because .... ; however, [blah-blah], their [blah-blah] root systems allow them to absorb [blah-blah].

So, we need to explain how Cacti can survive without water. Option (B) is clear and concise.

Cacti, like other drought-tolerant plants, can survive with little rain because of having the ability of retaining moisture through modified structures, such as spines and thick stems; however, when there is rain, their wide, shallow root systems allow them to absorb water quickly throughout a large area.

Ability to do something is the correct form

A. rain because of having the ability of retaining
having the ability of -> is unnecessarily wordy. I can do something or i am able to do something. I have the ability to learn quickly. I am having the ability of is wordy. this expression of having can clearly be replaced with simpler base verb forms.

B. rain because they are able to retain
because specifies the reason why they are able to survive. Is Cacti singular or plural? Cacti is plural. Cactus is singular. If confused, check the non-underlined part, it has 'their'...'them' that suggests it is a plural word. so 'they' refers to Cacti. 'Able to' is correctly used. Keep the answer!

C. rain, in their ability to retain
this option distorts the meaning. cacti can survive in little rain in their ability , is it trying to say they can survive in their ability to retain? doesn't make sense!

D. rain, having their ability to retain
Having their ability is used as a modifier to modify Cacti, if we restructure the sentence, Cacti having their ability to retain can survive. there is no need for modifier to represent Cacti.

E. rain, due to having the ability of retaining
based on the meaning, we are looking for reason to explain why Cacti can survive. we want the reason to explain the action of surviving. hence, because is appropriate for this construction. Also ability to is the correct form.

acti, like other drought-tolerant plants, can survive with little rain because of having the ability of retaining moisture through modified structures, such as spines and thick stems; however, when there is rain, their wide, shallow root systems allow them to absorb water quickly throughout a large area.

A. rain because of having the ability of retaining - having
B. rain because they are able to retain - correct
C. rain, in their ability to retain - subject comma rule
D. rain, having their ability to retain -having
E. rain, due to having the ability of retaining - having

Answer is B

Official Explanation:

Cacti, like other drought-tolerant plants, can survive with little rain because of having the ability of retaining moisture through modified structures, such as spines and thick stems; however, when there is rain, their wide, shallow root systems allow them to absorb water quickly throughout a large area.

A. rain because of having the ability of retaining
B. rain because they are able to retain
C. rain, in their ability to retain
D. rain, having their ability to retain
E. rain, due to having the ability of retaining

A review of our choices reveals a split between the forms of “retain.” We have the infinitive (to retain) and a preposition + -ing word. There is also a split between the use of “ability” or “able to.”

Every answer choice has either “ability” or “able” in the sentence, and these two words involve idioms that have very specific rules. They must always be followed by an infinitive. An infinitive is the word “to” + the base form of a verb. “Ability” and “able” are never followed by any other preposition, like of. So, Options A and E cannot be the correct answers.

Now, we need to consider our sentence as a whole, and because it is a modifying phrase, the part enclosed in commas can be safely ignored for a while. “Cacti can survive with little rain . . . they are able/their ability to retain moisture.” This sentence starts with mentioning how cacti can survive with little water and then mentions their ability to retain moisture. The sentence is attempting to set up a cause and effect statement. “In their ability to retain” and “having their ability to retain” does not show this causal relationship and, instead, seem to merely make a comment about their ability to retain moisture as if it is separate from their surviving with little rain. “Because” does show the causal relationship. Options C and D cannot be the best answer.

Option B is the best answer.

Thank you TestPrepUnlimited for another great explanation!

Well done, sampriya! You cracked the code on this one! Part of why option C is so awkward is because "in their ability to maintain" doesn't show the proper cause-effect relationship. Using "because" fixes this in option B.

Kudos to you!

Well done Raxit85! You caught both the idiom error and the cause-effect error! I also like that you wrote out your thinking process on this, so others can see how you figured things out.

Well done mykrasovski! You cracked the code!

I'm curious to know more about how you got to the correct choice using verbs from the non-underlined part of the sentence as your guide. This wasn't really the focus of the question's official explanation, but it's always great to hear how other people tackle these SC questions!

Well done snoep! I like that you caught the slight distinction between "because" and "due to!" The phrase "due to" is only used to modify nouns, not actions - and you got it! Great explanations on the rest, too!

Kudos to you!

Great job, HighModeOn! You cracked the code on this one! It would be nice to know more about what you mean when you say options A, D, & E are wrong because of "having." What type of error is that? It may help others who are reading over the comment section to know your thinking process on each of these.

Hi EMPOWERgmatVerbal I looked at the part that starts with "however". It talks, in general, about Cacti when there is rain. And the discussion is in Present Simple tense, because it is a fact. The first part talks about polar situation - when there is no rain - and this situation is also a fact. So, why would we use "fancy" tenses if there is a Present simple option without any flaws?

If I were to provide an example, I would say something like this (very silly example lol):
Bob brushes his teeth after dinner on weekdays. However, Bob skips brushing his teeth on Fridays since he attends parties.

Thanks for the added information, mykrasovski! We always like to hear the different ways people tackle these questions.

Hello from the GMAT Club VerbalBot!

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