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).
600 grams is the answer