Question

How does a single-celled fertilized egg grow into an adult in human beings?

Answer 1

The male gamete, sperm is inseminated inside the female vagina by copulation. Fertilization occurs with ovum in the fallopian tube. Following fertilization, the embryonic stage of development continues until the end of the 10th week (gestational age)

• The embryo in the next few days travels down the fallopian tube dividing several times to form a morula. Further cellular division is accompanied by the formation of a small cavity between the cells. This stage is called a blastocyst. The blastocyst reaches the uterus at roughly the fifth day after fertilization. The embryo becomes embedded in the endometrium in a process called implantation. Embryo undergoes differentiation, so as to produces the varied cell types (such as blood cells, kidney cells, and nerve cells). The time period of foetus development until birth is called gestation.
• Foetal development inside the mother's body takes approximately 9 months, where the foetus derives its nutrition, after which the parturition leads to the birth of the developed human baby, which then acquires nutrition via food consumption and grows into a complete adult.