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.
The fees and processing times are the same as for a regular passport application. Canadian passports are issued for a maximum period of five or ten years (for an adult 16 years of age or over) and five years (for a child under 16 years of age). There are no extensions beyond the five or 10 year validity.