Thank you for the information. I think I understand it now. I have been using RM for about 4 years and finally have the time to start trying to understand all of its features.
Since many of my ancestors married between the same families in the small community, I have no simple descendant tree unless I use only the descendants and spouse or descendant only if I understand you correctly.
Can someone explain the difference between "Everyone in the highlighted persons tree" and "Descendants of highlighted person" "Descendants and collateral lines" under the Export GEDCOM screen. When I export a GEDCOM using either one of these, the number of people is the same. I have read through Bruce's book and have not been able to find any reference to these. Thanks for the help.