Igcse Model Questions Vol1 2017 Biology Question 18
Practice objective / multiple choice question 18 from the 2017 Igcse Model Questions Vol1 Biology examination.
The labelled diagram shows the human respiratory system. In a healthy adult at rest the partial pressure difference for O₂ between alveolar air and pulmonary capillary blood is 60 mmHg. The rate of O₂ diffusion (\(R\)) is directly proportional to the alveolar surface area (\(A\)) and inversely proportional to the membrane thickness (\(T\)): \(R\propto \frac{A}{T}\). A disease reduces the alveolar surface area by 30 % and increases the membrane thickness by 20 % while the pressure difference remains unchanged. By what percentage does the rate of O₂ diffusion change compared with normal?
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About This Question
This is Igcse Model Questions Vol1 2017 Biology Question 18. It is one of the objective questions from the 2017 Igcse Model Questions Vol1 Biology examination.
Difficulty level: Medium .
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