The layer of soil in polar tundra that is always frozen is called permafrost. Permafrost is mostly located in places of high latitude.
I think its A) A antigens
the importance of water is that it will make you survive and it will make you feel fresh
I think that is might be the last one, I'm not all that sure though
The reason that organisms have common and scientific names is because there has to be a universal name for all organisms in theory.
Common names can be many different things, dependent on the area of the world you live in, Scientific Names are part of a series called <em>binomial nomenclature </em> which is a universal way to name all organisms. For example, a goose will be called <em>anser anser</em> across the world, then it changes some when you go into breeds, but for the most part, you can get by with that name.