Answer:
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
Santa shakes his belly like a bowl full of me
I am drawn by everyone without pen or pencil
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. What am I?
In spring, I am gay in handsome array. In summer, more clothing I wear. When colder it grows, I fling off my clothes. In winter, quite naked appear. What am I?
When is it bad luck to see a black cat?