My husband and I *love* to walk ...for hours and hours, and if we decide to go ahead with this potential trip - I'm going to need good shoes. These days, I have some reasonably good shoes for the most part - but they are 2-3 hour walking shoes, not necessarily good for 6+ hours of tromping around.
In cell biology, selective permeability is the property of a living cell membrane that allows the cell to control which molecules can pass through the membrane, moving into or out of the cell.
âº If a substance is permeable, it allows liquids or gases to go through it: Certain types of sandstone are permeable to water. The solvent passes through the permeable membrane to the solution. Soft and gas-permeable contact lenses are kinder to the eyes than hard lenses. Opposite. impermeable.