ANATOMY

Detailed explanation-1: -embryo, the early developmental stage of an animal while it is in the egg or within the uterus of the mother. In humans the term is applied to the unborn child until the end of the seventh week following conception; from the eighth week the unborn child is called a fetus.

Detailed explanation-2: -The germinal stage is the shortest stage of fetal development. It begins at conception when a sperm and egg join in your fallopian tube. The sperm fertilizes the egg and creates a zygote. The zygote begins its journey down to your uterus over the course of about one week.

Detailed explanation-3: -The developing embryo is called a blastula following completion of cleavage. Gastrulation: the dramatic rearrangement (movement) of cells in the blastula to create the embryonic tissue layers. These tissue layers will go on to produce the tissues and organs of the adult animal.

Detailed explanation-4: -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-5: -In the embryonic period of development, the zygote is referred as the embryo. After about 8 weeks the embryo is called the foetus. Foetus is the developing organisms from the end of the eight weeks until birth (nine months).