- (a) With reference to Figure 4(a), outline how glacier retreat may impact water resources in Switzerland. [1]

(b) With reference to Figure 4(b), calculate the percent decrease in ice volume between 1850 and 2019. [1]

(c) Describe the processes leading to the development of a pioneer community as the glacier retreats, as shown in Figures 4(c) and 4(d). [2]
Figure 4(c): photograph of glacier‑adjacent terrain

(d) Describe a method used to collect the data on percent cover vegetation shown in Figure 4(d). [3]
