Answer:
What is it that you must give before you can keep it.
What is pronounced like one letter, written with three letters. And belongs to all animals?
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.
Salty water everywhere but not sea in sight.
Bright as diamonds, Loud as thunder, Never still, A thing of wonder.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?