Re using slides and activities in another Captivate module

To add to Rod's answer - maybe he missed that you are talking about a 'responsive' project, which probably means that you are using fluid boxes.  That complicates everything a lot. Did you create a custom theme, which includes the object styles, master slides etc? Be sure to use the same theme for the destination project. Advanced actions triggered by slide events can be a problem as well. Whenever possible I would advise to use shared actions, to make the transition easier. But maybe you don't use shared nor advanced actions?

You can copy entire slides from one project file to another and Captivate will bring across any related variables or Advanced Actions, but there are several caveats.

You should make sure the projects are both of the same dimensions in height and width otherwise things may not line up as you expect.

Captivate will ensure that no objects are able to have object names that would conflict with other objects already residing in the target project.  If such conflict would occur it will usually add some numbers on the end of the imported object names to ensure uniqueness.  At times this can mean that the Advanced Actions will need to be partially or completely rebuilt. 

Also be aware that if your Advanced Actions contained actions to jump to another slide, those actions will likely be reset to Continue once everything is copied into the new project because the previous target slide does not exist there.

These are just a few of the things to look out for.  But the short answer is that you CAN normally copy slides and interactions from one project to another.