Answer:
I am needed for most animals and hardcover books. What am I?
Some will use me, others not. Some have remembered, others forgot. For profit or gain, I'm used expertly. I can't be picked off the ground or tossed into the sea. What am I?
I am a red drum which sound without being touched and grow silent when I am touched.
I am an object which is used in baseball. During the day I can't be seen at all. What am I?
The eight of us go forth not back to protect our king from a foe's attack. What are we?
When is it bad luck to see a black cat?