Answer:
My first is in fish but no in snail. My second is in rabbit but not in tail. My third is in up but not in down. My fourth is in tiara but not in crown. My fifth is in tree you plainly see. My whole a food for you and me.
I am there when you sit, but gone when you stand. What am I?
I am the key that is the hardest to turn
I am used when you jump off a bridge for fun.
I am expelled from you orally with a sound
I tell people to be careful when handling boxes.