Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs. It occurs in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.
Admitted for 180 days â Canadians admitted in âVisitor for Pleasureâ or B-2 status without a B-2 visa in hand are deemed to be admitted for 180 days under current US Customs and Border Protection (CBP) interpretation of the rules.
Visit Canada to determine where you would like to live and the logistics of moving your belongings there, should your application for permanent residency be accepted. Americans with a valid U.S. passport, passport card or NEXUS card can stay in Canada for up to 180 days without having to apply for a Canadian visa.