Explain why communist systems can evolve into totalitarian states.

Why does physical weathering speed up the processes of chemical weathering? a) physical weathering requires abundant water, as does chemical weathering. b) physical weathering produces fresh surfaces for chemical weathering to attack. c) chemical weathering can occur only on small surfaces, not large ones. d) chemical weathering requires salt, which is provided by salt wedging.

[fw.02]sinkholes are often formed as a result of the actions of. a. heat on recharge b. pressure on aquifers c. acid in groundwater d. minerals in hot springs

What is the mostly tropical region in asia