Answer:
I am perfect with a head perfect without a head; Perfect with a tail perfect without a tail; Perfect with either neither or both.
What begins with T ends with T and has T in it?
I belong to you but others use me more often than you do. What am I?
Two bodies have I, though both joined in one. The more I stand still the faster I run. What am I?
Everyone in the world needs me. They generously give me but never take me. What am I?
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?