Recomendations and solution for river pollution

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 is the mercury length of time for one revolution around the sun?

What is the approximate chemical composition of the solar nebula?