Question 44·Medium·Boundaries
After earning a degree in mechanical engineering, Gabriela Torres began researching biodegradable _____ she later patented a process that converts agricultural waste into eco-friendly packaging materials.
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundaries questions, first confirm whether each side of the blank is an independent clause (subject + verb). If both sides are independent clauses, only a few boundaries work: comma + coordinating conjunction, semicolon alone, or a period. Then eliminate choices that create run-ons, double connectors (semicolon + conjunction), or capitalization errors after a period.
Hints
Find the subjects and verbs
Underline the main subject and verb before the blank and then do the same after the blank. Are there two full clauses (each with its own subject and verb)?
Check what comes right after the blank
Does the word after the blank start a new clause with its own subject ("she")? That often means you need a strong boundary or a comma + conjunction.
Match each punctuation pattern to a rule
Between two independent clauses, look for:
- comma + FANBOYS, or
- semicolon alone, or
- period (and then correct capitalization in the next sentence).
Eliminate double-connector choices
If you see a semicolon (or a period) plus a coordinating conjunction doing the same joining job, that choice is usually wrong.
Step-by-step Explanation
Identify the clause before the blank
Read from the start up to the blank: "After earning a degree in mechanical engineering, Gabriela Torres began researching biodegradable _____."
Filling in the noun "plastics" gives: "Gabriela Torres began researching biodegradable plastics." This is an independent clause (subject "Gabriela Torres" + verb "began researching").
Identify the clause after the blank
Read the part after the blank: "she later patented a process that converts agricultural waste into eco-friendly packaging materials."
This is also an independent clause (subject "she" + verb "patented").
Choose a correct boundary between two independent clauses
Because both sides are independent clauses, you need a correct boundary. Common correct ways include:
- comma + coordinating conjunction (FANBOYS)
- semicolon by itself
- period (start a new sentence with correct capitalization)
Test the choices
- "plastics, and" correctly uses a comma + coordinating conjunction to join two independent clauses.
- "plastics; and" is a double connector (semicolon already joins clauses; adding "and" is incorrect here).
- "plastics and" creates a run-on because two independent clauses are joined with no comma.
- "plastics. and" is incorrect because a new sentence must begin with a capital letter.
Therefore, the best choice is "plastics, and".