(a(i))[2]
Explain why stem cells are needed in places such as the lining of the small intestine.
(a(ii))[1]
Name the mitosis stage shown in cell X in Fig. 2.1.
(a(iii))[1]
State which part of the cell cycle is shown at Y in Fig. 2.1.
(b)[2]
Explain the function of centromeres in the cell cycle.
(c)[6]
Fig. 2.2 shows three kinds of specialised cell that develop from Lgr5$^+$ stem cells in the small intestine. Suggest a function of each of the cells shown in Fig. 2.2, and explain how the structure of each cell supports your suggestion.