Question 240·Hard·Boundaries
By 1864, the London Zoological Gardens had assembled what was then the world's largest collection of living _____ feat made possible by a network of colonial agents, naval officers, and private donors who transported specimens from around the globe.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation and sentence-boundary questions, first determine whether the segments around the punctuation are independent clauses or fragments. Eliminate options that treat a fragment as a sentence (e.g., with a period or semicolon). When the second part explains or renames the first clause, a colon is often appropriate. Always test the sentence with your chosen option to ensure it is both grammatical and logical.
Hints
Check for a complete sentence on each side
Decide whether the words before the blank form an independent clause, and whether the words after the blank can stand alone as a complete sentence.
Name what comes after the blank
The words after the blank start with “a feat made possible…”. Is that an independent clause, or is it a descriptive noun phrase?
Match punctuation to purpose
If the second part explains or restates the first clause, choose punctuation that introduces an explanation (rather than punctuation that joins two complete sentences).
Step-by-step Explanation
Identify the structures on each side of the punctuation position
All choices place punctuation immediately after the word “animals.” The text to the left—“By 1864, the London Zoological Gardens had assembled what was then the world's largest collection of living animals”—is a complete independent clause. The words that follow the punctuation begin with “a feat made possible by a network of colonial agents, naval officers, and private donors...,” which is a noun phrase (not a complete clause).
Decide what relationship the second part has to the first
The phrase beginning with “a feat” explains the accomplishment in the first clause (it renames/elaborates on the idea). So you need punctuation that can attach an explanatory restatement to a complete clause, not punctuation that requires another independent clause to follow.
Use punctuation rules to narrow the choices
Eliminate any choice that incorrectly treats “a feat made possible...” as a complete sentence:
- A semicolon can join two independent clauses, so it won’t work if what follows is just a phrase.
- A period would start a new sentence, but “A feat made possible...” would be a fragment.
- A comma + and typically signals coordination (joining two independent clauses or two parallel items), which doesn’t fit an explanatory phrase like this.
Confirm the best-fitting choice
The remaining option correctly links the complete clause to an explanatory phrase:
“By 1864, the London Zoological Gardens had assembled what was then the world's largest collection of living animals: a feat made possible by a network of colonial agents, naval officers, and private donors who transported specimens from around the globe.”
Therefore, the answer is animals: a.