Answer:
By Moon or by Sun, I shall be found. Yet, if there's no light around, I am undone. What am I?
I can be sweet or sour. I do not rhyme with any other word
I am pronounced as one letter, written with three. I come in blue, black, brown, or grey. Reverse me and I read the same either way. What am I?
I am edible pink and a great summer food
Lovely and round, I shine with pale light. Grown in the darkness, a lady's delight. What am I?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.