In a paragraph where does the controlling idea usually appear?
a. in the first sentence
c. in the middle of the paragraph
b. in the second sentence
d. in the last sentence

the two answers are

get thee back into the tempest and the night's plutonian shore

on the pallid bust of pallas just above my chamber door

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).