<prompt> One intern calculated the concentration of O2 in blood as 0.0025 mlml of blood. Considering atmospheric pressure as 760mmHg, how much approximate O2 tension could have been in the blood?40 mmHg60 mmHg80 mmHg100 mmhg  <response>: For PO2 to be 100mmHg, the dissolved O2 level has to be around 0.30mldL of blood.So when the O2 level is 0.25mldL, the PO2 is around 80mmHg. 