Mass- the amount of in an object

What two properties affect the density of ocean water

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.

Ascientist makes a map using gis. one layer is an aerial photograph of farmland. other layers show water level changes and how crop cover has changed over time. what might the scientist be studying?