Two leaves are photosynthesising in the light. Air moves across leaf X, while the air around leaf Y is still.
How does the moving air allow leaf X to take up carbon dioxide faster than leaf Y?
It increases the distance carbon dioxide travels from the leaf surface to the cells, so the rate of diffusion into the cells increases.
It replenishes carbon dioxide at the leaf surface as carbon dioxide enters the cells, so a concentration gradient into the cells is maintained.
It removes carbon dioxide from the leaf surface as carbon dioxide enters the cells, so the concentration gradient into the cells becomes steeper.
It makes the carbon dioxide concentrations at the leaf surface and in the cells equal, so net diffusion into the cells continues.
102 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.