Your audio imported as a single, stereo file. and your timeline also has a track that is a single track, but a STEREO track. There are two types of tracks...Mono and Stereo. Stereo tracks are good because they allow you to use a single track for a stereo file, instead of wasting space on two tracks for this same file...since we rarely, if ever, make changes to one channel, but not the other.
You can change the clip if you want...just right-click on it, choose MODIFY then AUDIO CHANNELS. And then in the PRESET drop down menu, choose MONO and you'll get two mono channels that you can do with what you will