CHIRANJEEV SINGH
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Question

Normally a bone becomes fossilized through the action of groundwater, which permeates the bone, washes away its organic components, and replaces them with minerals.

Option A
Option B
Option C
Option D
Option E

(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)

Solution

Sentence Analysis

  • Normally a bone becomes fossilized (Main Subject: A bone; Main Verb: becomes)
    • through the action of groundwater, (Prepositional phrase modifying the main verb)
      • which permeates the bone, washes away its organic components, and replaces them with minerals. (Dependent clause modifying ‘groundwater’ – Subject: which; Verb: permeates, washes, and replaces)

The sentence says that generally, a bone becomes fossilized through the action of groundwater. The groundwater does three things: permeates the bone, washes away its organic components, and replaces the organic components with minerals.

The sentence is correct as is.

Option Analysis

(A) Correct.

(B) Incorrect. This option has a deterministic parallelism error. The three elements in the list are:

  1. which permeates the bone
  2. which washes away its organic components
  3. which those are replaced with minerals

Since the third element is incorrect grammatically and logically (doesn’t make sense), the list is incorrect.

(C) Incorrect. The main error with this option is ‘to be replaced’. ‘to be replaced’ denotes the purpose of the verb ‘permeates’, leading to the meaning that groundwater permeates the bone with a purpose to be replaced with minerals.

‘washing away…components’ can be treated as a ‘comma+verb-ing’ modifier for the clause ‘which permeates’. ‘washing away its organic components’ could be a direct consequence of ‘permeating’, so this construction is not incorrect.

(D) Incorrect. For the following reasons:

  1. ‘to be replaced’ denotes the purpose of the verb ‘becomes’, leading to the meaning that the bone become fossilized with a purpose to be replaced with minerals.
  2. Logically, ‘permeating’ and ‘washing’ make sense with ‘groundwater’. However, in a ‘comma+verb-ing’ structure, the verb-ing doesn’t go with anything other than the subject.

(E) Incorrect. For the following reasons:

  1. 2nd error of option D
  2. A comma is missing before ‘and’. Since the list contains three elements, we need to have a comma before ‘and’.

If you have any doubts regarding any part of this solution, please feel free to ask in the comments section.

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4 Comments

  1. Hi CJ,
    Since after “which” the list contains three items, the last one is – “which replaces them with minerals”.
    Now, the sentence will be read – “Normally a bone becomes fossilized … action of groundwater, which replaces them with minerals”
    But groundwater doesn’t replace the bone with minerals, rather the organic components with minerals right?
    So, isn’t that an error in Option A? Both washing and replacing should be a direct consequence of permeating the bone right?

    1. How can ‘them’ refer to ‘bone’, which is singular.

      ‘them’ refers to organic components, and it makes sense to say that groundwater replaces organic components with minerals.

      “washing” and “replacing” can be consequences of “permeating”. However, the existing parallel structure is fine. Remember that you need to be generally careful/open with meaning-based issues.

  2. Hi CJ,

    Thank you for your explanations. They’re great.

    The verbing is confusing me in option E. The rule for comma + verbing modifier is that it should GENERALLY make sense with the subject of the preceding clause. And you pointed out in one of the official questions that verbing was okay even thought it wasn’t making sense with the subject of previous clause. So why can’t we apply that learning here? I’m all over the place. Earlier I wasn’t aware of too many rules and I feel I was better off. How can I improve?

    Thank you in advance!

    Best,
    Ashmit

    1. In cases where verb-ing doesn’t make sense with the subject, it makes sense with the clause.

      In this case, something needs to be ‘permeating’ the bone. In no case, a comma+verb-ing at the end of a clause modifies the preceding noun. Thus, ‘permeating’ cannot go with ‘groundwater’ grammatically.

      The only noun that ‘permeating’ can go with, from a grammar point of view, is the subject. This is not going to make sense.

      Does it help?

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