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P6 Science

Question post on Fri, 03/06/2022 8:34pm

Hi, anyone can help?

Liew Nga Wing · Answer 1 · Post on Sat, 04/06/2022 2:05pm

My answer is (1) “B” only because X position is where the blood with lower exygen and impurities entering the air sac and Y position is where the “fresh blood” with higher exygen level leaving the sac to other parts of the body so A and C are wrong. For D, it is also wrong because: in human exhaled air contains about 70% nitrogen, 16% oxygen, at a few percent of water vapor and carbon dioxide and small amounts of other gases, therefore not only carbon dioxide is expelled from air sac.