Answer:
I'm as simple as a circle worthless as a leader; but when I follow a group their strength increases tenfold. By myself I'm practically nothing.
I make billions of dollars selling windows. Who am I?
My voice is tender my waist is slender and I'm often invited to play. Yet wherever I go I must take my bow or else I have nothing to say.
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
I belong to you but others use me more often than you do
I flow from the Homer’s mouth when he sees doughnuts.
What am I?
Animal
Difficult
Easy
Food
Funny
Kids
Logic