Sentence Improvement

Directions: This question presents a sentence, all or part of which is underlined. Beneath the sentence you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is the best, choose the first answer; otherwise choose any one of the others.

A smile can be observed, described, and reliably identified; it can also be elicited and be manipulated under experimental conditions.