Across • Address • Affects • Areas • Balance • Borders • Boundaries • Cooperation • Creating • Definition • Destruction • Development • Differences • Directions • Ecosystems • Enhance • Essential • Exacerbate • Extends • Form • Growth • Habitats • Important • Investments • Isolationism • Issues • Multiple • Natural • Neighboring • Occur • Opportunities • Past • Plants • Preserving • Purpose • Region • Rivers • Role • Sharing • Significance • Single • Some • Something • Territorial • Thing • Trade • Transboundary • Two • Type • Urban