Polar caps of Mars: Is dry ice an important element for the hold of life?

Question

I've been told that the polar caps of Mars are made out of dry ice.That's frozen carbon dioxide.
Well,what kind of ice is that,does it contain water?
Is dry ice of any importance for the hold of life?
What if it's melted somewhere...would it be possible that there are some kind of little lakes in mars,from the melting of this ice?

Answer 1

Life cannot exist without liquid water. There IS water ice at the poles, but most of it is buried under a layer of dust. The visible polar ice cap that grows and shrinks every year is all carbon dioxide ice, commonly called dry ice. It cannot support life.

Answer 2

even if dry ice melts, it sort of skips over the liquid phase (there is a term for this but i cannot think of it), hence the term dry ice. it goes straigh from ice to gas and could indeed be valuable to life on mars. operating under the same principles as life on earth, all life depend on either photosynthetic or chemosynthetic organisms. these organisms make glucose (the basic 'food' unit of life) by using either the suns energy in conjunction with co2 and water, or other energy from sulferous gases in some cases (although this is reletively rare). in either case, it is absolutely essential that co2, or some other, most likely gaseous, form of inorganic carbon be present. remember though, that this is operating under the principles of life on EARTH and that life on mars my operate completely differently.