Answer:
I am the heart that does not beat. If cut, I bleed without blood. I can fly, but have no wings. I can float, but have no fins. I can sing, but have no mouth.
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.
It is by nature, soft as silk; A puffy cloud, white as milk; Snow tops this tropical crop; The dirtiest part of a mop
There is one word that stands the test of time and holds fast to the center of everything. Though everyone will try at least once in their life to move around this word, but in fact, unknowingly, they use it every moment of the day. Young or old, awake or in sleep, human or animal, this word stands fast. It belongs to everyone, to all living things, but no one can master it. The word is?
I am rarely touched but often held. If you are smart you'll use me well. What am I?