Vitamins
When spelt, it is a question, When shouted, it is a command, It is great for your health, But stiff on the sand. What is it?
I can be good for you, I can be bad, I can be found all over inside and outside your body. I am microscopic, single-celled and have no nucleus.
You may praise your good fortune and curse all you hate, Yet I rule all your chaos and gamble your fate. By some I'm avoided by others I'm game, Called by fat or slim, my meaning's the same.
What am I?