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 have a straight back and sharp teeth to cut objects.
What is the beginning of eternity the end of time and space the beginning of every end and the end of every race?
Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers magazines and journals.
I am what no man ever yet did see, which never was, but always is to be. What am I?
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.