Thanks for the Sansa Clip suggestion. It looks like I'll definitely have to buy a compatible device to listen to audible books because audible will not play on just any MP3 player. They're as protectionist and anti-competitive as Australian publishers.
No rock is completely impermeable, but some porous rocks like shale and pumice are mostly impermeable, because the pores are not interconnected, thus not allowing fluids or gases to pass through them. This is why shale makes a good cap-rock, and pumice floats instead of sinking.
Best Answer: Selectively permeable is NOT the same as semi-permeable. A piece of dialysis tubing is semi-permeable; some solutes go though depending on their size. A CELL MEMBRANE is selectively permeable because its permeability changes from time to time, depending on the cell's needs.it SELECTS what it is permeable to... piece of dialysis tubing is semi-permeable; some solutes go though depending on their size. A CELL MEMBRANE is selectively permeable because its permeability changes from time to time, depending on the cell's needs. it SELECTS what it is permeable to...