Igcse Model Questions Vol1 2025 Biology Question 13
Practice objective / multiple choice question 13 from the 2025 Igcse Model Questions Vol1 Biology examination.
The diagram shows a labelled cross‑section of the human lungs. It indicates that the left lung contains 300 million alveoli and the right lung 350 million alveoli. Each alveolus is approximated as a sphere with an inner radius of \(0.09\ \text{mm}\). (a) Calculate the total inner surface area of all alveoli (in square metres) that is available for gas exchange. (b) If the effective surface area is reduced by 12 % due to a disease, what is the remaining surface area? Give your answers to two significant figures.
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About This Question
This is Igcse Model Questions Vol1 2025 Biology Question 13. It is one of the objective questions from the 2025 Igcse Model Questions Vol1 Biology examination.
Difficulty level: Medium .
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