Uninstalling modules, specificially ANSWERS
If a module doesn't delete its tables or content in hook_uninstall, then the content is not automatically removed when you disable the module.

You can see here that answers does not clean up after itself when it is uninstalled, probably for good reason.

If you want to purge everything, you will need to delete the nodes, fields, and bundles manually at admin/content and admin/structure/types or by writing some code that uses field_delete_field() or field_attach_delete_bundle().