Based on the answers provided, the following corrections need to be made to the 3D object:

1. Add a slotted groove running from the bottom to the top of the plate. This groove should be located at the center of the front profile of the rectangular plate.
2. The groove should be created by subtractively extruding a small rectangle. 

Please ensure that the groove does not alter the overall rectangular shape of the plate or the ratio of its width to its height.