Precipitation happens as a result of water evaporating and condensing. When water evaporates the water molecules transfer to a gas state into the atmosphere as water vapor. This water vapor then condenses due to cooler air temperatures because of this condensation larger water droplets form. Once these droplets become so large they can no longer be considered water vapor they will fall back down to earth. The act of these droplets falling is what is known as precipitation.
If the membrane of a cell were no longer selectively permeable then "<span>The cell would die as it would not be able to regulate which substances could enter and leave", since a selectively permeable membrane allows both things to enter and leave for the cell's survival. </span>
