Look at the outline.
what type of organization will this essay use?
types of friends
i. acquaintances
a. people you hardly know but say “hi” to anyway
ii. family friends
a. your family
b. friends of your family
iii. good friends
a. people you see on a regular basis, at least once a week
iv. best friends
a. people you talk to or see everyday
a. chronological order
b. simple list
c. order of importance
the answer is c.

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).