What is one of the main functions of the ovaries?

The ovaries play a crucial role in the female reproductive system primarily by producing the hormones estrogen and progesterone. Estrogen is vital for the development of female secondary sexual characteristics, regulation of the menstrual cycle, and overall reproductive health. Progesterone prepares the uterine lining for possible implantation of a fertilized egg and helps maintain pregnancy.

In contrast, testosterone and sperm production are functions associated with the male reproductive system, specifically the testes. Regulating blood sugar levels is primarily the role of the pancreas, and filtering toxins from the blood is a function of the kidneys. Thus, the production of estrogen and progesterone is the primary function of the ovaries, making this the correct answer.