What Am I Riddles

Question: I'm written with two letters, said with one and seen with two.What am I?

Question: Something all men have,
but all men deny.
Man created it,
but no man can hold it.

What is it?

Question: What sport starts with a T, has four letters, and is played around the world?

Question: Voiceless it cries,
Wingless flutters,
Toothless bites,
Mouthless mutters.

What is it?

Question: What gets easier to pick up the larger it gets?