Answer:
The Titanic is still here.
I am lighter than air but a hundred people cannot lift me. Careful! I am fragile!
I help engines spin and pants stay up.
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?
When I am caught, I am thrown away. When I escape, you itch all day. What am I?
Runs over fields and woods all day. Under the bed at night sits not alone, With long tongue hanging out, Resting at your feet until we go for a walk