Simple riddles

Everyone has it and no one can lose it, what is it?

I am a nut with a whole. What am I?

I have no life, but I can die, what am I?

It is just something that everybody does at the same time. What is that?

I don't have wings, but I can fly. I don't have eyes, but I will cry! What am I?

What has four legs, but can't walk?

I am always hungry and will die if not fed, whatever I touch will soon turn red.

What has a neck but no head?

I have keys but no locks. I have a space but no room. You can enter, but can't go outside. What am I?

I live in the ocean. I swim wherever I want. I sing to my family. I can breathe through a hole in the top of my head. I am a...