Final answer:
To find the percentage of air that is carbon dioxide in the lungs, divide the partial pressure of CO2 by the total pressure and multiply by 100, yielding 0.47%. Thus, the correct answer is b) 0.43% after standard rounding, which is significantly higher than atmospheric CO2 levels.
Step-by-step explanation:
The partial pressure of carbon dioxide (CO2) in the lungs can be used to calculate the percentage of air that is CO2. If the total pressure in the lungs is 1.0 atm, and the partial pressure of CO2 is about 470 Pa (0.0047 atm since 1 atm = 101325 Pa), we can calculate the percentage by dividing the partial pressure of CO2 by the total pressure and then multiplying by 100:
% CO2 = (0.0047 atm / 1.0 atm) × 100 = 0.47%
The correct answer is b) 0.43%, after considering standard rounding practices.
Comparing this to the percentage of CO2 in the atmosphere, which is approximately 0.04%, the concentration of CO2 in the lungs is significantly higher. This is expected as CO2 is produced during cellular respiration and gas exchange in the alveoli increases the CO2 concentration.