According to the In Focus box titled "What You Really Want to Know About Sleep," yawning is:
A) caused by too much carbon dioxide in a person's blood.
B) typically followed by an increase in a person's activity level.
C) caused by too little oxygen in a person's blood.
D) not contagious.

Question

Quizplus · Accepted Answer

Yawning is typically followed by an increase in a person's activity level, as it is believed to help increase alertness and readiness for action.

According to the in Focus Box Titled "What You Really