differentiate between zygote, embryo and foetus
A zygote is the fertilized cell that will grow into a baby animal. When a female's ovum and a male's sperm cell unite, this cell is called the zygote. The zygote then multiplies, and grows into an embryo. A zygote is the cell that results from fertilization. A zygote is synthesized from the union of two gametes, and constitutes the first stage in a organism's development.
Embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. In humans, it is called an embryo until about eight weeks after fertilization and from then it is instead called a fetus.A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.
Foetus - In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.