Answer:
Although I am still, in families I run. I continue to live on in a living one. As one continues to draw breath, I will not rust. However, when one stops drawing breath, I will become mere dust. What am I?
I am needed for most animals and hardcover books. What am I?
I'm not a bird, but I can fly through the sky. I'm not a river, but I'm full of water. What am I?
You use me between your head and your toes the more I work the thinner I grow.
I am very afraid of doing scary activities.
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.