How did the increasing amounts of oxygen in earth atmosphere allow organisms to live on land

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.

What causes the cyclical changes in the appearance of the moon?

Where would you be most likely to find a freshet?