Blog menus not working on Tablets or Smartphones

When I try to view my blog on a Tablet or Smartphone, the menus don’t work correctly. I can select a dropdown, but the content is not displayed.
I do not speak code, and the answer to my question may be there, but I can’t figure it out.
Blog is: https://www.photographyandtravelforthephysicallychallenged.com/
Cansomeone help an old man?