... buildings have disappeared.(A) If iron were(B) iron is being(C) Since iron is(D) How iron is 15. The starting point for the formation of petroleum is that has accumulated in die sedimentson ... of Venus. Venus, slightly closer to the Sun than Earth and thus hotter, had no'oceans in 15 which the carbon dioxide could dissolve or life to help take up the carbon.Also, Venus has probably ... stocked with waterfowl and plant products, Native Americans used mudshoes (built similarly to 15 snowshoes) to keep from sinking in the mud.Canoes and rafts were osed by Native Americans in...