Answer:
I am not alive but I grow I don't have lungs but I need air I don't have a mouth but water kills me. What am I?
I walk on 4 legs in the morning 2 legs at noon and 3 legs at night.
I lose my head in the morning and regain back it at night.
I run up and down the stairs without moving. What am I?
If you have me you want to share me. Once you share me you won’t have me.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?