Which slide should you change so that it reflects on all the slides on all of your presentation. any change that you make to the will reflect throughout the slides of your presentation.

Top most slide (Slide Master)

Any change that you make to the slide master will reflect throughout the slides of your presentation.

Explanation:

While making presentations in Microsoft PowerPoint, we often need a quick way to implement changes like themes, fonts or layout into all the slides at once. For this quick implementation, we click the top most slide that is relatively bigger than all others and then choose the formatting options like layout or background. The selected theme will be applied on all the slides.

So this topmost slide is known as Slide Master.

To view the Slide Master, go to the view tab of PowerPoint and select Slide Master order in order to view and edit the slides as required.

i hope it will help you!

idk i had the answer