Blood flows continuously through capillaries surrounding an alveolus.
How does this help oxygen continue to diffuse into the blood?
It carries absorbed oxygen away, increasing the alveolar wall thickness.
It brings oxygen-rich blood in, maintaining a concentration difference.
It carries absorbed oxygen away, maintaining a concentration difference.
It brings oxygen-rich blood in, increasing the alveolar wall thickness.
42 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law. Each one has a worked solution and a mark scheme showing where the marks go.