What kind of key can't fit in a lock but can turn a handle without any doubt

I am both male and woman, I live where most living things couldn't, I always frown though my name suggest I shouldn't, What am I?

I’m not quite a bug and not yet with wings, I’m a little green house where a sleepy worm sings. I wiggle inside as I dream of the sky, Then break my small shell and learn how to fly. What am I?

I have no lungs but I am alive. I need water to survive. I'm up and about night and day, I go with the flow, you might say.

I sizzle like bacon but I'm not in a pan I have a backbone but no legs or hand I shed my old skin to stay feeling new And I fit in a hole or slide through the dew