(a)[1]
Draw a label line and add a label on Fig. 4.1 to identify a phloem sieve tube.
(b)[2]
Describe the role played by phloem sieve tubes.
(c)[3]
In the root tip, some cells formed by mitosis go on to differentiate into xylem vessel elements. As this differentiation happens, the structure of the cell wall changes. Explain how the walls of xylem vessel elements are adapted to their functions.
(d(i))[3]
Calculate the surface area to volume ratio for an animal represented by a cube with side length $0.1\,\text{m}$. Show your working.
(d(ii))[2]
The surface area to volume ratio gets smaller as animals become larger. Use this fact to suggest why multicellular animals need transport systems.