Answer:
I wonβt break if you throw me off from the highest building but I will break if you place me in the ocean.
As I went over London Bridge I met my sister Jenny; I broke her neck and drank her blood and left her standing empty.
A single syllable do I claim black was my most famous name; Fetal to mortals here below thousands have I slain in a single blow.
I have no head and a tail I lack but I do have arms and legs and back; I inhabit the palace the tavern the cot 'tis a beggarly residence where I am not. If a monarch were present (I tell you no fable) I still should be placed at the head of the table.
I am owned by the poor the rich does not need me. If you eat me you will die!
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.