What kind of logical fallacy appears in this passage?
in the metamorphosis, gregor samsa is a terrible and frightening person. we know this because all of the members of his family react to him with fear and horror.
a) circular argument
b) appeal to authority
c) ad hominem attack
d) slippery slope

This is an example of a circular argument. To support the statement that Gregor is frightening, the writer merely says that others are afraid of him.

adding more details about the struggle rainsford experiences as he swims to the shore

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).