What common english word is 5 different letters long, and each time you remove a letter from it, it still remains an english word?

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

i'm not sure what the second paragraph is but a decree is an official order issued by legal authority. find the one that best fits this definition.