Answer:
David's father has three sons: Snap Crackle and ?
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
I help engines spin and pants stay up. What am I?
I am found in the sea and on land but I do not walk or swim. I travel by foot but I am toeless. No matter where I go, I am never far from home. What am I?
I am an insect half of my name is another insect. I am similar to the name of a famous band.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.