How to disable select and activate and return to just select tool How to disable the select and move tool  and return to just select tool in the blender interface

I'm using Blender 2.8 on Ubuntu 18.04 with default settings.
Toolbar buttons with a little arrow at the bottom right can be expanded to reveal more sub-tools or options.

Just click continuously on the Selection Tool toolbar button to expand the dropdown, and pick any of the available tools from there.