Earth compared to all its water and air

I don't know. I mean, the earth is quite big and oceans aren't that deep compared to it. Earth is basically as smooth as a marble.

That is true but only 2.5% of the total water on earth is safe to drink, but we can only get 1% as the other 1.5% is water of the ice of glaciers

water covers 70% of the earth's surface, but it is at most little more than 7 miles in depth. the earth's crust alone is over 30 miles in depth in places. the total diameter of the earth is 8000 miles.