Water is considered a polar molecule because

Polarity is when a molecule has a little bit of a charge on one side that's different from a charge on the other side so think of a north pole and a south pole when thinking of polarity.

So polarity is going to be a molecule that has different charges on the molecule so the bigger the difference in charge, the more polar. To make the definition easier, you can say that polarity is a difference in charge across a molecule.

Water is polar because it has a little bit of a negative charge on one end and a little bit of a positive charge on the other end so that's why water would be considered polar.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.