Which feature maintains a steep oxygen concentration gradient at the alveoli?

  1. Mucus in the alveoli
  2. Continuous blood flow through capillaries
  3. Few alveoli
  4. Thick alveolar walls
Answer

B) Continuous blood flow through capillaries

Blood carries O₂ away. AS & A Level Biology · Topic 9 Gas Exchange · 9.1 The gas exchange system

Biology MCQ · More A Level Biology: Gas exchange MCQs · Practise