The problem with multiple choice tests.
Read question 12 (real question from a real test, issued to students).
None of the optional answers correspond with areas where trees are actually growing.
Therefore, a student may reason, “Maybe there’s a pollution problem with the island (or too rocky) and trees are not able to grow there. Perhaps the flood plain is regularly flooded and trees are not able to grow there because of the moisture variability. The base of the mountain may be an especially poor place for trees to grow due to frequent rock slides. And with climate change, the mountain top may be suitable habit for trees to grow as the area warms, especially since there are already a number of trees growing on the mountain.”