Material through which water flows is permeable. This material can be either natural or artificial. Naturally permeable material can be clean sand and gravel for example, or a sandstone and in the latter case the sandstone can have both porosity which is not synonymous with permeability as the pores must be connected to be permeable. An impermeable membrane could be used to line ditches for example to prevent leakage near mines.
Both prokaryotic and eukaryotic cells have structures in common. All cells have a cell membrane, ribosomes, cytoplasm, and DNA. The cell membrane, or plasma membrane, is the phospholipid layer that surrounds the cell and protects it from the outside environment.
