GMAT Verbal Practice, Sentence Correction
The capacity of embryonic stem cells to develop into most types of human tissue, which makes them potentially valuable for medical applications, but the genetic program that underlies this quality is not yet known.
- tissue, which makes them
- tissue makes them
- tissues, which make them
- tissue, making them
- tissue make it
The clause preceding the word but and the one following it are each intended to be independent — that is, each one should stand as a complete sentence in itself. However, the first clause lacks a predicate, and the result is a so-called "run-on" sentence. By simply removing the word which and the comma preceding it, the problem is solved and the result is a sentence that makes sense. (The singular noun capacity takes the singular verb form makes.) The correct response is (B).