Can I add a subset of questions that are unique where the main set is common?

I want to add a subset of questions (which will have unique answers) from the original set (which will be common) and I want to do so in a manner so that multiple subsets can be submitted with the original (common set) remain in place.  Much like when uploading files and you have to select to "add another"  only this would be for a set of fields - instead of one field.

Thanks!

I'm not sure if I understood your question, but I would like to recommend you the Configurable List widget: https://widgets.jotform.com/widget/configurable_list 

This guide will help you configuring it: https://www.jotform.com/help/282-How-to-Set-Up-the-Configurable-List-Widget 

You will also find more multiple entries widgets here: https://widgets.jotform.com/category/multiple_entries 

This guide will help you adding the widgets to your form: https://www.jotform.com/help/252-How-to-Add-a-Widget-to-Your-Form 

I hope this helps. 

Is there a way, using the configurable list, to create a line break, so that lengthy or additional fields drop below instead of going out all the way to the right, to have them "wrap" and stay within the width of the white space of the default design? 

I have read some feedback also, and it looks like the content - when exported, will be all in one cell of a spreadsheet.  Is that true?

Thanks!

You can customize the widget to be mobile responsive, please take a look on this guide where you will find the needed resources to achieve it: https://www.jotform.com/help/456-How-to-Make-the-Configurable-List-Widget-Mobile-Responsive 

I have read some feedback also, and it looks like the content - when exported, will be all in one cell of a spreadsheet.  Is that true?

Yes, the data sent in the widget will be in one single cell, so far it's not possible to split the data into different cells.