Respuesta :

Harry would need to change the "color scheme" to change the background of all his presentation slides.

Answer:

Harry needs to change the theme to change the background of all his presentation slides.

Explanation:

To change themes in powerpoint follow these steps: first, click on the Design tab  and then select one theme from the options .

Notice that themes also change the position, font, color and size of the text,  among others.