Although
all urban archaeological sites face similar challenges, the proximity to centers of population and the level of air-borne pollutants at the sites dramatically influences the duration and cost of the dig, as well as the likelihood of successful preservation.
a.all urban archaeological sites face similar challenges, the proximity to centers of population and the level of air-borne pollutants at the sites dramatically influences
b.each urban archaeological site faces a similar challenge, their proximity to centers of population and the level of air-borne pollutants dramatically influence
c.all urban archaeological sites face a similar challenge; their proximity to centers of population and the level of air-borne pollutants dramatically influences
d.each urban archaeological site faces similar challenges, the proximity to centers of population and the level of air-borne pollutants at each site dramatically influences
e.all urban archaeological sites face similar challenges, the proximity to centers of population and the level of air-borne pollutants at each site dramatically influence