4. Write a hypothesis about the size of molecules and ions that can cross the cell membrane vs. the size of molecules and ions that can not cross the cell membrane. (Please help!!)

climate change and pollution

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.