Moving Clips in the Timeline

The relink button above the media pool is enabled (red) only when clips are offline?

How can you select only the video or only the audio portion of a clip in the timeline?

Disable the "Linked Selection" button in the edit page tool bar.
Disable the "Relink Media" button in the Media Pool.
Alt or Option select the audio or video.
Disable the Auto Track Selector for the track (Audio or Video) that you do not want to select.

In the toolbar, what does clicking the blade icon allow you to do in the timeline?

It activates Blade edit mode which allows you to split a clip into sections in the timeline.
It splits the clip under the timeline ruler.
It performs the famous "Blade Edit" that was popularized by the Blade Runner films.

Which keyboard shortcut allows you to toggle between showing the entire timeline in the window and returning to the previous magnification level?

To move a clip in the edit page timeline, you must switch to the Blade tool.