Good Riddles

Question: I am important at the most dangerous times. I can not be seen, heard, or smelled. If you use me too much you would fatally die. What am I?

Question: When you close it, you see mysterious and funny looking images. But if you open it, the mysterious images are gone. What Am I?

Question: What key is playful?

Question: "Good morning!" - I appear again! Time for breakfast - I`m long as F*** Its dinner time - I`m crouching down Supper time approaches - I`m on my tippy toes "Good night!" - ...gone again... What am I?

Question: A murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, the second is full of assassins with loaded guns, and the third is full of lions that haven't eaten in 3 years. Which room is safest for him?