Human reproductive appearance photography

(1)(2)(3) Sperm produced by male testicles enter the vagina, slowly pass through the uterus, and meet the eggs produced by the ovary in the fallopian tube, and the sperm and the eggs combine to form fertilized eggs. Therefore, the formation site of C fertilized egg is ② fallopian tube.

(3)(4) The embryo continues to divide and differentiate in the mother's womb, forming various tissues and organs. In the eighth week of development, the embryo begins to look like a human, and the embryo from then until before birth is called a fetus. The passage of fetal production is vagina.

When the mother is pregnant for about 40 weeks, the fetus is mature, and the process of the mature fetus coming out of the mother's vagina is called delivery.

Therefore, the answer is: (1) sperm; ①

(2) fertilized eggs; ②

(3)③; vagina

(4) childbirth; 40.