(a)[2]
On Fig. 1.1, use label lines and letters to identify these parts: X - xylem tissue; P - palisade mesophyll tissue.
(b)[2]
The leaves of C. sinensis are broad and thin. Explain how each of these two characteristics helps the leaf to carry out photosynthesis.
(c(i))[1]
The lower epidermis contains stomata. State one structural difference between a guard cell and other lower epidermal cells.
(c(ii))[3]
Abscisic acid plays an important part in stoma closure. It causes potassium ions to leave guard cells. Outline how the loss of potassium ions from guard cells leads to closure of the stoma.