Answer:
Roast, boast, coast, post. What do you put in a toaster?
I sit in a corner while travelling around the world.
I save lives on the ground and in the air. What am I?
I come out of the earth, I am sold in the market. The one who buys me cuts my tail, takes off my suit of silk, and weeps beside me when I am dead. What am I?
Of the king I am blue and of the peasant I am red. Of the frog I am cold and of the dog I am hot instead.
I am a rock group with four members. All dead one was assassinated.