Audio tracks missing from timeline but still audible in sequence???

I created a 5-minute sequence and everything was great.  Then I wanted to fade out the audio track... and I could not find it.  It's obviously in the sequence because I can hear it.  But it's nowhere on the timeline.  I watched several videos on timeline navigation, figuring there must be an easy way to reveal the audio tracks, but no luck.  I tried all the navigation tips and I still saw no audio tracks, not even a blank one. The entire timeline consists of video tracks, although there are obviously audio tracks because I can hear them in playback mode.

I tried all the navigation tricks, including scrolling and holding the control key to move up and down -- but the bottom of the timeline just just shows video tracks, no audio tracks.

How can I get the timeline to show me the audio tracks?