Embryos are fully grown human beings in the early stages of development.
The term 'embryo,' like the phrases 'baby' and 'adolescent,' refers to a distinct and long-lasting organism in a specific developmental stage.
Development of human embryo:
After an egg is fertilized in humans, the embryo starts to develop four days later.
In the uterine wall, an embryo develops from blastocyst implants.
The blastocyst grows into an embryo linked to a placenta and surrounded by fluid-filled membranes inside the uterus, where it implants in the uterine wall.
The embryo is linked to a placenta, and it is surrounded by fluid-filled membranes.