Never start a job without knowing the adress that its at and the type of chemicals you are working with
Using more time and energy you obviously have not used your time and /or energy efficiency.
Answer: In the air sacs
Explanation: Air sacs has a million tiny holes that is were oxygen transfers. Inside the air sacs oxygen moves across paper thin walls to tiny blood vessels called capillaries into your blood
The oxygen enters the bloodstream from the alveoli.