Name the long narrow open area where many museums are located

Most of earths fresh surface water is found in

How much water is in the ocean in cubic kilometers

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone,pumice, and gneiss.