Ovaries!
estrogen
The ovaries in the female reproductive system produce estrogen and progesterone. They also store and mature the eggs.
Estrogen
a circulatory system
They are in ovaries.They are produced and work on ovaries
Two almond-shaped structures on either side of the uterus that release eggs and secrete the female hormones estrogen and progesterone
* circulatory system * digestive system * endocrine system * integumentary system * immune system * muscular system * nervous system * reproductive system * respiratory system There are actually more than nine. The ones not mentioned are: * skeletal system * excretory(urinary) system
excretory and circulatory
The circulatory system takes up oxygen, and releases carbon dioxide.
Reproductive system and endocrine system. Your ovaries produce the ovum for reproductive system. The ovary produce the estrogen and progesterone hormones for the regulation of the monthly cycle and are necessary for the reception and maintenance of the pregnancy.
What is the skeleton system
Estrogen is an important hormone in female organisms. Estrogen is responsible for causing feminine characteristics to arise, and plays a large part in the regulation of the females reproductive system.