Which of the following describes the author's main purpose of the text? A to explore why people and animals yawn and how yawns are
contagious
B to prove that yawning is more of a biological function than a social one
C to explain why scientists know so little about why humans yawn
D to support the theory that yawning helps cool down the brain

I would say A because it is the main idea and the others are details to support the main idea.

The main themes of the play are: fate and free will with the inevitability of oracular predictions is a theme that often occurs in greek tragedies the conflict between the individual and the state similar to that in sophocles’ “antigone” and   people’s willingness to ignore painful truths both oedipus and jocasta clutch at unlikely details in order to avoiding facing up to the inceasingly apparent truth and sight and blindness the irony that the blind seer tiresius can actually “see” more clearly than the supposedly clear-eyed oedipus, who is in reality blind to the truth about his origins and his inadvertent crimes.