(a(i))[4]
Explain why these results were obtained.
(a(ii))[3]
State three factors that influence the movement of molecules through membranes.
(b(i))[3]
Molecules of carbon dioxide that are produced in muscle cells are carried to the blood. Describe the route taken by these carbon dioxide molecules.
(b(ii))[3]
Explain how capillaries are adapted for their functions.
(c)[4]
Explain how a carbon dioxide molecule from the atmosphere reaches the site of photosynthesis in a leaf.