Semipermeable means something can be penetrated by a few things. that being said choices A and B can be eliminated.
Choice D would negate semi as it says all polar molecules, leaving choice C as the best answer
The Importance of Freshwater Ecosystems. Water ecosystems, specifically freshwater ecosystems, are some of the most important resources in the replenishment and purification of water sources used by humans. ... One of the main functions of wetlands is to remove metals and sediments that make their way into water.
