The figure is a sketch of the female reproductive system, please analyze and answer the following questions. (1) The organ shown in Figure ③ is _ _ _ _ _ _ _ _, and its function is _ _ _ _ _. (2) Fertilization. The picture shows the structure of female reproductive system, which mainly includes ① uterus, ② fallopian tube, ③ ovary and ④ vagina.

(1), as shown in Figure ③, is the ovary, which is the main reproductive organ of women and can produce eggs and secrete estrogen.

(2) As shown in the figure, the egg enters ② fallopian tube about 8 ~10 minutes after it is discharged from ③ ovary, reaches the junction of fallopian tube and isthmus through the umbrella of fallopian tube, and stays in ampulla. If it meets sperm, it will be fertilized here to form a fertilized egg. It can be seen that the place where human egg cells combine with sperm is ② fallopian tube. After that, the fertilized egg moves and divides continuously, and finally implants on the inner wall of [5] uterus, and develops slowly in ① uterus.

(3) The embryo takes about 40 weeks in the mother's body, that is, 280 days, and is delivered from the vagina after it matures. This process is called delivery.

Therefore, the answer is: (1) Ovary and egg-producing cells secrete estrogen.

(2) [2] fallopian tube, [1] uterus?

(3) [4] Vagina