All I Need

What would I take stranded in a desolate land? With the choice of only having one specific item I hold so close. This item would be essential in my dire situation. The one element that can keep me alive in the absents of food. It comes down when the clouds swell to heavy. It flows and twists like a snake or stampedes by with the force of a hundred elephants. It can shape shift into any form it is held in. It is what aids our bodies function properly like a well oiled vehicle. The one element that makes life flourish with a single drop. Water. Such a simple object with astonishing power. The only object that would preserve me from the arid desert.