EVERYDAY SCIENCE

Detailed explanation-1: -The embryonic stage lasts through the eighth week following fertilization, after which the embryo is called a fetus. The embryonic stage is short, lasting only about seven weeks in total, but developments that occur during this stage bring about enormous changes in the embryo.

Detailed explanation-2: -Fertilization results in the formation of zygote which begins to develop into an embryo. The zygote divides repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body. This developing structure is termed an embryo.

Detailed explanation-3: -It is the stage of development between the zygote or fertilized egg and the newly formed offspring, formed by repeated mitotic division of the zygote. It is formed due to the fusion of male and female gametes through fertilization or syngamy.

Detailed explanation-4: -By Day 5, the embryo, now called a blastocyst, is about 70-100 cells. A blastocyst has differentiated and contains two different cell types. The first is called the inner cell mass, which develops into fetal tissue. The second is called the trophoblast or trophoectoderm, and these cells lead to part of the placenta.