Yes. This cannot be done using the filter options on the "Explore" (main) page of Sora, but it can be done using the "search for a book" feature.
Follow these steps to select more than one option for the audience level filter:
1) Go to the "Search for a book" section (or magnifying glass)
2) Select the "filters" button
3) Go to the "Audience" section of the filter and choose the options that you would like to see (juvenile, young adult, general adult)
Your filter preferences will be saved. To change them, repeat the steps above.
