Which of the following is not a secondary sexual character observed in females at puberty?

The secondary sexual characters appear in humans when they attain the age of puberty. Hormones play an important role in the appearance of secondary sexual characters. 

In females, eggs develop in the ovaries and ovulation occurs, breasts develop and become enlarged and hips become broad.

In boys, the larynx grows and becomes prominent in the front of the neck. It is thus known as Adam's apple. 

Thus, Adam's apple is not a secondary sexual character observed in females at puberty.