<span>We stretched and then slowly jogged once around the track</span>
The people will have journeyed to the center of the earth. I think this because it is the title. This is fantasy because the center of the earth is too hot to travel to. The people will probably get burnt next.
Extraneous means irrelevant or unneeded. essential means absolutely needed.
so they are opposites.
The other opposites in that set are mediocre (meh average) and extraordinary(amazing)
D
