Researcher Lin Zhi developed a process for increasing the tensile strength—measured in gigapascals, or GPa—of silkworm ________dissolving and reweaving the silk in a solution of iron metal ions, zinc, and sugar, Zhi increased the amount of force required to stretch it from approximately 0.5 GPa to 2 GPa.
Which choice completes the text so that it conforms to the conventions of Standard English?
Explanation
Context: The sentence has two independent clauses: "Zhi developed a process for increasing the tensile strength of silkworm silk" and "By dissolving and reweaving the silk...Zhi increased the amount of force required to stretch it from approximately 0.5 GPa to 2 GPa." A period separates them.
Answer: D) silk. By
Why? A period correctly separates two independent clauses. The second sentence begins with "By dissolving and reweaving the silk" as an introductory prepositional phrase, followed by the main clause.
Traps:
- A) silk, by → comma splice; two independent clauses cannot be joined by a comma alone
- B) silk by → run-on; no punctuation between the two independent clauses
- C) silk and by → "and" is a coordinating conjunction but requires a comma before it; "and by dissolving" would also change the meaning