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.
Report Abuse. 6 months in Canada as a VISITOR and then 6 months OUTSIDE of Canada before you can enter Canada again BUT if the immigration people at the border think you are trying to LIVE in Canada illegally then you will be denied entry.Sidwell Â· 6 years ago. Thumbs up.0.est Answer: 6 months in a one year period is the maximum. You can return back for a short visit, but be aware that Canadian immigration will calculate how many days you've been in the country in one given you and can either deny or cap your visit to a few days.