Examkin

Question

Difficulty: MediumPunctuation of Nonessential Elements

The following passage is from a text about the discovery of a rare tree species. Read the passage and determine which punctuation mark best completes the sentence.

In 1994, field officer David Noble discovered a small grove of unusual trees in a remote canyon within Australia's Wollemi National Park. These trees—later named Wollemi pines (Wollemia nobilis){{blank_1}} represent one of the greatest botanical discoveries of the twentieth century. Previously known only through fossil records dating back millions of years, the species offers scientists a rare window into prehistoric ecosystems. Because fewer than a hundred mature trees exist in the wild, the exact location of the grove remains a closely guarded secret to protect them from disease and damage.

Which punctuation mark must be inserted into the blank to correctly set off the nonessential element?

Answer:In 1994, field officer David Noble discovered a small grove of unusual trees in a remote canyon within Australia's Wollemi National Park. These trees—later named Wollemi pines (Wollemia nobilis)【—】 represent one of the greatest botanical discoveries of the twentieth century. Previously known only through fossil records dating back millions of years, the species offers scientists a rare window into prehistoric ecosystems. Because fewer than a hundred mature trees exist in the wild, the exact location of the grove remains a closely guarded secret to protect them from disease and damage.

Answer

An em dash (—)
The correct punctuation mark is an em dash (—). The phrase 'later named Wollemi pines (Wollemia nobilis)' acts as a nonessential appositive phrase that provides additional information about 'These trees'. Since this nonessential element is opened with an em dash (—), it must be closed with an em dash to maintain grammatical symmetry and avoid mixing different types of punctuation.

Step-by-Step Solution

1
Identify the nonessential element in the target sentence.
The phrase 'later named Wollemi pines (Wollemia nobilis)' is a nonessential element modifying 'These trees'.
A nonessential element provides extra information that is not essential to the core grammatical structure of the sentence.
2
Examine the punctuation that begins the nonessential element.
The nonessential element starts with an em dash (—) after the word 'trees'.
To maintain punctuation symmetry, a nonessential element that begins with an em dash must also end with an em dash.
3
Determine the appropriate punctuation mark to close the nonessential element.
An em dash (—) must be inserted at the blank position to properly close the parenthetical information.
Using any other punctuation mark, such as a comma or parenthesis, would result in punctuation asymmetry.

Key Concept

Punctuation of Nonessential Elements
Rate this question

Topics

Punctuation of Nonessential Elements

More questions from this topic