ALL the DIFFERENT ORGANISMS interacting in a lake make up a .

is this for the e2020 class

if you know your abc's you should be able to get your answer or just use google

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.