The answer is the Transition element.
A slide transition in PowerPoint occurs when you move from one slide to another during a presentation. You can control the speed (time spend on a single slide before advancing to the next). We use set duration to set the transition speed. To set the transition speed to a shorter or a larger duration, select the slide and click on the Transitions tab in the Timing group. In the Duration box, type the number of seconds that you want.