True or false? if a paragraph contains sentences which do not relate to the topic sentence, the paragraph lacks unity

true

hope this helps!

True

For a paragraph to have unity, its sentences need to coincide (go together). Like if you are writing about a certain subject in that paragraph, you would need to stay on that particular subject and not go on about another subject in the same paragraph

the answer is d: message a character's thoughts

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).