Answer:
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.
Jack and Jill when up the hill jack fell down
A precious stone, as clear as diamond. Seek it out while the sun's near the horizon. Though you can walk on water with its power, try to keep it, and it'll vanish in an hour.
You can only have it once you have given it.
Talks like this, a green wise man does. Guess my clue, you will.
A first job for many kids, this could be described as "Media Distribution Management.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?