Answer:
I am needed for most animals and hardcover books
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 am a vegetable that bugs stay away from
Although it sounds like I work on a transportation device I actually work in a restaurant.
Although I may have eyes I cannot see. I have a round brown face with lots of acne.
Two brothers we are, great burdens we bear. All day we are bitterly pressed. Yet this I will say, we are full all the day, and empty when go to rest.