Yes. You can copy business objects, rules and other configuration elements from one business space to another, or duplicate them within the same business space. To do it, right-mouse-click (Control-click on Mac) on the desired configuration element in the configuration tree panel on the left and select Copy from the context menu. In the destination business space version, right-mouse click on the appropriate container in the tree (such as 'Business objects' for copying business objects) and select Paste from the context menu.
> What happens to linked and other dependent objects?
The attributes referring to non-existing objects will remain unresolved. The integrity checker will detect them. You can either copy the other dependent objects across, or delete the attributes referring to non-existing objects from the copied object if they are not relevant to the destination business space.