The protective sac around the embryo or fetus is the amniotic sac.
A developing embryo becomes a fetus at around 8 weeks after fertilization. At this point, the major organ systems have started to form and the embryo takes on a more human-like appearance.
For the first 8 weeks the developing human is called an embryo after that it is called a fetus.
The amniotic sac is the sac in which the fetus develops in amniotes. Its wall is the amnion, the inner of the two fetal membranes. It encloses the amniotic cavity and the embryo.
The stage in the embryo called a fetus typically begins around the 9th week of development. At this point, the major organs have formed and the developing organism is referred to as a fetus until birth.
After the 8th week, the embryo is called a fetus.
Fetus zygote is not the term to use. A zygote is a fertilized egg. An embryo is a developing baby. A fetus is a baby before it is born.
In the seventh week of the embryo's development
Fetus
A zygote is formed when a sperm cell fertilizes an egg cell. It is a single cell that later divides and develops into an embryo. An embryo is the early stage of a developing organism, typically from around 2 weeks to 8 weeks after fertilization. A fetus is the later stage of prenatal development, usually starting around 8 weeks after fertilization until birth.
A developing baby in the womb is called a fetus after it has completed the embryonic stage, which ends around the 8th week of pregnancy.
The cotyledon protects the embryo
Gene combination and their expression in the embryo