Which of the following is the order of pCO2 from low to high?

A.Exhalation ＜ tissue cell ＜ venous blood ＜ alveolar gas

B.exhalation ＜ alveolar gas ＜ venous blood ＜ tissue cell

C.exhalation ＜ alveolar gas ＜ tissue cell ＜ venous blood

D.venous blood ＜ exhalation ＜ alveolar gas ＜ tissue cell

正确答案：exhalation ＜ alveolar gas ＜ venous blood ＜ tissue cell