Why do alveoli have a rich capillary network?

  1. To make mucus
  2. To maintain a steep concentration gradient
  3. To keep the airways open
  4. To trap dust
Answer

B) To maintain a steep concentration gradient

Blood flow carries gases away, keeping the gradient. O Level Biology · Topic 9 Human Gas Exchange · 9.1 Human gas exchange

Biology MCQ · More O Level Biology: Human Gas Exchange MCQs · Practise