Question 25·Easy·Boundaries
Because sloths move so slowly, algae grow on their fur; the algae provide _____ allowing sloths to blend in with the surrounding canopy and avoid predators.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation/boundaries questions, always first identify what is on each side of the punctuation: is each side a complete sentence, a phrase, or a clause that depends on something earlier? Remember that semicolons and periods can only separate complete sentences. Commas can link a sentence to dependent or modifying phrases, such as -ing (participial) phrases. Quickly test each option by reading the sentence with that punctuation and asking: does this create a fragment or a run-on, or does it smoothly and logically connect the parts of the sentence?
Hints
Check what comes after the blank
Focus on the words that follow the blank: "allowing sloths to blend in with the surrounding canopy and avoid predators." Ask yourself if this is a complete sentence by itself or something that depends on the earlier part.
Think about semicolons and periods
Semicolons and periods are used to separate two complete sentences (independent clauses). Consider whether the words after the blank could stand alone as a full sentence.
Consider how -ing phrases attach to a sentence
The word "allowing" ends in -ing and introduces extra information. How are such phrases usually connected to the main clause: with strong punctuation (like a semicolon or period), or with lighter punctuation (like a comma)?
Compare "no punctuation" vs. "comma"
If you read the sentence aloud with no punctuation before "allowing," does it sound like something is missing where a small pause should go? Which choice best marks that brief pause without breaking the sentence into fragments?
Step-by-step Explanation
Identify the sentence structure around the blank
Read the full sentence:
"Because sloths move so slowly, algae grow on their fur; the algae provide camouflage _____ allowing sloths to blend in with the surrounding canopy and avoid predators."
Before the blank, we have the complete clause "the algae provide camouflage." After the blank, we have "allowing sloths to blend in with the surrounding canopy and avoid predators."
Decide what kind of phrase "allowing sloths to blend in..." is
"Allowing sloths to blend in..." begins with the -ing verb "allowing" and does not have its own subject. It depends on "the algae" from the previous clause. This makes it a participial phrase that adds extra information about the result of the algae’s camouflage, not a new independent clause.
Recall punctuation rules for participial phrases
A participial phrase that gives extra, nonessential information at the end of a sentence is normally set off from the main clause with a comma. We do not use a semicolon or a period before such a dependent phrase, because those marks are reserved for separating complete sentences (independent clauses). Leaving out the comma entirely would incorrectly run the main clause directly into the participial phrase.
Test each answer choice against these rules
Now evaluate each option:
- Using a semicolon before "allowing" would separate the main clause from a fragment, which is incorrect.
- Using a period and starting with "And allowing" would also create a fragment.
- Using no punctuation at all would fail to set off the participial phrase.
- The remaining option places a comma before "allowing," correctly attaching the participial phrase to the main clause.
Therefore, the correct answer is B) camouflage, because the comma properly connects the main clause with the following participial phrase.