Answer:
The strangest creature you'll ever find has two eyes in front and a hundred behind.
I turn around once. What is out will not get in. I turn around again. What is in will not get out.
What is lighter than what it is made of?
In we go, out we go. All around and in a row. Always, always steady flow. When we'll stop, you'll never known. In we go, out we go.
You get many of me, but never enough. After the last one, your life soon will snuff. You may have one of me but one day a year, When the last one is gone, your life disappears.
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?