Pumice is a volcano rock that is commonly light enough to float
Answer:
Vestigial structure. Hope this helps :P
Explanation:
Cell membranes enable organisms to maintain homeostasis by regulating the materials that may enter or leave a cell.
There are different materials of raw water, but also the raw water comes from ponds,rivers, and oceans but they might be good sometimes, and gas not been treated and has bacteria or mold buy that is not good.
