Answer:
What goes with a car, comes with a car, is no use to a car but a car cannot move without it?
What is the heart of many risks, has a heart, but is not a living being?
I am a good state, there can be no doubt of itΝΎ But those who are in, entirely are out of it.
Come up and let us go. Go down and here we stay.
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
I repeat only the last word you say. The more I repeat, the softer I got. I cannot be seen but can be heard. What am I?