Why do we use marble fanlight sills and door thresholds instead of other materials similar to wood? I need to know why marble thresholds are used surrounded by certain...

I need to know why marble thresholds are used surrounded by certain parts of the country and not others? Would you buy one instead of another stuff?
How 2 compost?
Answers:    we do use other things
Bed bugs?!!?!?
they are like a tootsie roll they second a long time
wood on the other hand will rot briskly