What Am I Riddles

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

What is it?

Question: I am there !!! but I was!!!

Question: What is as big as you are and yet does not weigh anything?

Question: Without me, nothing exists. What am I?

Question: I have four feet in total, two that I stand on and two that I don't . What am I?