Human-made (synthetic) fibers used in clothes and many other consumer products are more durable than most natural animal ______ blank

Question

Human-made (synthetic) fibers used in clothes and many other consumer products are more durable than most natural animal blank the manufacture of synthetic fibers requires toxic chemical solvents that can pollute air and water.

Which choice completes the text so that it conforms to the conventions of Standard English?

Accepted Answer

Choice D is the best answer. The convention being tested is the coordination of main clauses within a sentence. This choice correctly uses a comma and the coordinating conjunction &ldquo;but&rdquo; to join the first main clause (&ldquo;Human-made...fibers&rdquo;) and the second main clause (&ldquo;the manufacture...water&rdquo;). Choice A is incorrect because it results in a comma splice. Without a conjunction following it, a comma can&rsquo;t be used in this way to join two main clauses. Choice B is incorrect because when coordinating two longer main clauses such as these, it&rsquo;s conventional to use a comma before the coordinating conjunction. Choice C is incorrect because it results in a run-on sentence. The two main clauses are fused without punctuation and/or a conjunction.

Question human-