Examkin

Question

Difficulty: Very hardCommas with Lists, Clauses, and Coordinate Adjectives

While exploring deep-sea hydrothermal vents, astrobiologists identified several unstable, vibrant, complex, organic, compounds, and they hypothesized that these chemicals could support microbial life.

Which of the following choices best punctuates the underlined portion of the sentence?

  1. A
    NO CHANGE
  2. unstable, vibrant, complex organic compounds, and theyAnswer
  3. C
    unstable, vibrant, complex organic compounds, they
  4. D
    unstable, vibrant, complex organic compounds; because they

Answer

The choice that correctly punctuates the coordinate adjectives with commas, leaves the cumulative adjective and noun unseparated, and uses a comma before the coordinating conjunction to join the two independent clauses.
The correct choice properly separates the coordinate adjectives 'unstable', 'vibrant', and 'complex' with commas, while correctly omitting a comma before the cumulative adjective 'organic' and the noun 'compounds'. It also places a comma before the coordinating conjunction 'and' to separate the two independent clauses.

Step-by-Step Solution

1
Determine if the adjectives modifying the noun are coordinate or cumulative.
The adjectives 'unstable', 'vibrant', and 'complex' can be reordered and separated by 'and' without changing the meaning of the sentence, so they are coordinate adjectives and require commas between them. However, 'organic' is a cumulative adjective that functions as a single unit with the noun 'compounds' ('organic compounds'), so no comma should separate 'complex' from 'organic', nor should a comma separate 'organic' from 'compounds'.
Correctly applying adjective comma rules prevents punctuation errors in descriptive sequences.
2
Identify the clause boundary and determine the correct punctuation to link them.
The sentence consists of two independent clauses: the first ends with 'compounds' and the second begins with 'they hypothesized'. These clauses are connected by the coordinating conjunction 'and', which must be preceded by a comma.
Joining two independent clauses with a coordinating conjunction requires a comma before the conjunction to avoid comma splices or run-on sentences.
3
Combine the adjective punctuation and clause punctuation to evaluate the options.
The correct combination is 'unstable, vibrant, complex organic compounds, and they'.
This option properly formats both the coordinate/cumulative adjective sequence and the independent clause boundary.

Key Concept

Coordinate vs. Cumulative Adjectives and Clause Boundaries
Rate this question

Topics

Commas with Lists, Clauses, and Coordinate Adjectives

More questions from this topic