Answer:
Mars does have an atmosphere, but it is about 100 times thinner than Earth's atmosphere and it has very little oxygen.
Smooth ER<span>, by contrast, is not associated with </span>ribosomes<span>, and its </span>functions<span> differ. The </span>smooth ER<span> is involved in the synthesis of lipids, including cholesterol and phospholipids, which are used in the production of </span>new<span> cellular membrane.</span>
the very basic properties of water
conducts heat
neutral pH
high surface tension
high specific heat
good solvent
how does this help a polar bear, some of it is a stretch but possible benefits
pH - good drinking water, good for marine ecosystem for food
high specific heat - can absorb lots of heat before the temperature rises, polar bears exist naturally in cold environments. (ice) - maybe can tie this in with the natural hibernation cycle
high surface tension - I'm assuming the polar bear walks on the ice at times to get fish
as a good solvent - its probably good that most things dissolve in water, otherwise we would have a lot of floating gunk on top of the water
outside of this, can't give you much more. it has been noted in Shishmaref Village that the ice caps melting is leading to a lack of water in higher mountain areas and polar bears are coming down from the mountain ice cap areas to find food and water
Because it allows only certain substances to permeate. If it was totally permeable that would be good enough to having no barrier as it would let everything though. Totally impermeable means that nothing would get through.