Science: Mass Movement, Glaciers & Weathering?

[minni]

Why can the removal of vegetation trigger mass movements?
a). The soil loses nutrients and begins to crumble
b). The plant roots bind the soil and regolith together
c). The plant roots lubricate the loose sediment

One characteristic of glacial movement is:
a) new snowfall accumulates in a zone at the bottom of a glacier
b) the zone of wastageis at the top of a glacier
c) the movement depends on the balance between accumulation and wastage.

Chemical weathering would be:
a) most effective in a warm dry climate
b) most effective in a cold dry climate
c) most effective in a warm humid climate