Correct the underlined part in the following sentence:
A growing technology trend is to merge multiple devices with complimentary functions such as a phone, music player and the scheduling features of a planner.

The sentence is incorrect because it does not follow parallelism. A list that begins by naming devices (i.e. phone, music player) must continue and finish in that way. Although it is informative to include the details about a planner's features, it should be accompanied by the features of a phone and a music player if that is the way the sentence is being written. Adding “and” again making the sentence read “...music player and and...” is clearly wrong!