a lung is a kind of organ for breathing air & in order to breath air you must take in air ->  a lung is a kind of organ for taking in air  a lung is a kind of organ for taking in air & the lungs are a part of the respiratory system ->  the respiratory system takes in oxygen from the air  converting oxygen from air into oxygen from blood means absorbing oxygen from air into the blood & breathing is when a lung converts from oxygen in air into oxygen in blood ->  blood absorbs oxygen in the lungs  blood absorbs oxygen in the lungs & if something is absorbed by something else, then that something is transferred to that something else ->  the lungs transfer oxygen to the blood  the lungs transfer oxygen to the blood & the lungs are a part of the respiratory system ->  the respiratory system transfers oxygen to the blood  the respiratory system transfers oxygen to the blood & blood is a part of the circulatory system ->  the respiratory system transfers oxygen to the circulatory system  the respiratory system transfers oxygen to the circulatory system & to transfer can mean to move ->  the respiratory system moves oxygen to the circulatory system  the respiratory system takes in oxygen from the air & the respiratory system moves oxygen to the circulatory system -> the respiratory system takes in oxygen from the air to be moved by the circulatory system