Answer:
I'm blue, but when you see me I'm red. You don't see me too often. I'm there for you if you're hurt, but I'm good for you. What am I?
I store fire-breathing animals.
I can be written, I can be spoken, I can be exposed, I can be broken. What am I?
You buy me to eat, but never eat me. What am I?
I am essential to life on earth! I am split into thirds. Two thirds are the same. One of the thirds is 8. The other two are 1 each.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.