When adjusting the bounding box around the text, holding the Shift key allows you to scale proportionately, while holding the Ctrl key enables you to skew the object.
When you hold down the Shift key while resizing or adjusting the bounding box, it maintains the aspect ratio or proportions of the object. This means that if you drag one handle of the bounding box to make the object larger or smaller, it will resize uniformly in both the horizontal and vertical directions.
As well, holding down the Ctrl key (or Cmd on Mac) while adjusting the bounding box allows you to skew the object. Skewing transforms the object by tilting it along one axis while keeping the other axis unchanged.
For example, we can skew a rectangle to make it appear as a parallelogram. This can be handy for creating various design effects or for aligning objects at specific angles within your document.
The full question is:
When adjusting the bounding box around the text, holding the ____ key to scale proportionately or the ____ key to skew the object.