Answer:
What is black when it's clean and white when it's dirty?
I'm not alive but I grow I don't have lungs but I need air I don't have a mouth but water can kill me. What am I?
You see a boat filled with people. It has not sunk but when you look again you don't see a single person on the boat. Why?
I save lives on the ground and in the air. What am I?
Break me and I am better, immediately set and harder to be broken again. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?