New slides can be added to a presentation by

Searching on GOOGLE

Explanation:

Yea sorry it matters what slide-show site you are using. For an example if you are using Google Slides then there is a little plus mark on the top left corner above the pages you have. Sorry but that's the only Slide Show site I use so if you are using something that isn't Google Slides then search it up on Google. Google knows (Mostly) everything.

answer; i do believe its (d) modem;