rahuldandekar

WEll, in reply to the original question, i may give some reasons why f=ma and not mv :

First, a body having no net external force which acts on travels with const. velocity where the constant can be zero. So we need something called 'Force' to explain changes in motion, not the motion itself. It's acceleration that is the measure of changes in motion. We define force such that it is proportional to the acceleration. The constant differs from object to object, and we denote it by 'm' and call it 'mass. So, we write f=ma .

Water is a polar solvent. That is why it can dissolve many compounds.

If we are looking for carbon-based life, then water is the best place for life molecules to form. Also, the first life organisms didn't use oxygen, but hydrogen from the water, liberating oxygen. Thats why our atmosphere changed to 20% oxygen. Thats why the ozone layer formed.