Question

Difficulty: MediumRun-on Sentences and Comma Splices

Geologists studying the 1815 eruption of Mount Tambora have analyzed volcanic ash preserved deep within polar ice cores. These microscopic particles provide a precise chronological record of atmospheric sulfur concentration, however, trace element signatures also reveal the exact global temperature shifts that followed the cataclysmic event.

Which choice best corrects the punctuation error in the underlined portion?

  1. A
    NO CHANGE
  2. concentration; however, trace element signatures also revealAnswer
  3. C
    concentration; because trace element signatures also reveal
  4. D
    concentration. Although trace element signatures also reveal

Answer

The option using a semicolon followed by 'however' and a comma accurately resolves the comma splice by properly joining two independent clauses.
The correct choice places a semicolon before the conjunctive adverb 'however' and a comma after it, which is the standard rule for connecting two independent clauses without forming a comma splice or run-on sentence.

Step-by-Step Solution

1
Identify clause boundaries
Two distinct independent clauses are present: 'These microscopic particles provide a precise chronological record of atmospheric sulfur concentration' and 'trace element signatures also reveal the exact global temperature shifts...'
Both clauses contain a subject and a predicate and can express complete thoughts on their own.
2
Evaluate the transition word and punctuation
The word 'however' acts as a conjunctive adverb, not a coordinating conjunction.
Conjunctive adverbs cannot join independent clauses with just commas; doing so produces a comma splice.
3
Select the correct punctuation pattern
A semicolon before 'however' and a comma following it properly connects the independent clauses.
A semicolon is grammatically strong enough to link independent clauses joined by conjunctive adverbs.

Key Concept

Run-on Sentences and Comma Splices
Rate this question