Which action will result in a visual gap in the Timeline if applied incorrectly?

When selecting multiple clips in the Timeline without handles, it can lead to a situation where there is no overlapping media between the clips. Handles are the extra media at the beginning or end of a clip that allow for transitions or edits without cutting into the content itself. If clips do not have these handles, any attempt to apply a transition or a similar effect could create a gap, as the software doesn't have enough media to perform the desired operation without resulting in a visual discontinuity.

This action specifically highlights the importance of understanding the media's boundaries and the lengths of clips within the edit. Without handles, any intent to connect or blend those clips visually will be disrupted, leading to a clear visual gap in the Timeline.