What forms as a result of collisions and separations between tectonic plates?

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.

Which environment would most likely not contain fossils? a a thick deposit of cracked, dried mud b sediment deposited in a sandy river bed c intrusive rock formed from cooled magma d layers of sand accumulated for a century

These factors threaten north americas ecosystems