If the partial pressure of oxgyen at the alveoli is 100 mmHg, and the partial pressure of oxygen at the tissue cells is 40 mmHg, then the partial pressure of oxgyen in the systemic arteries is:
Question 1 options:

1)

100 mmHg

2)

70 mmHg

3)

40 mmHg

4)

140 mmHg

5)

60 mmHg

6)

46 mmHg