Answer:
I have three heads. Cut off one I become stronger. Cut off two I become ten.
I am the ultimate killing machine used not once but TWICE I can be made by humans.
Sometimes I am white, sometimes I am dark. Most people love me. What am I?
I have a foot but no leg. What am I?
You use a knife to slice my head but you weep beside me when I am dead
Dry though I may be, I am still a sea.