How do twins happen? Fraternal vs. Identical

Fraternal - 2 egg cells

Identical - split of zygote

Explanation:

Fraternal twins are likely to be formed by 2 different egg cells being simultaneously sent by the ovaries and both of them being fertilized by the sperm cells. They are non-identical because the DNA of the 2 egg cells and the 2 sperm cells are different.

Identical twins are formed after a single egg cell has been fertilized by a single sperm cell, then split after the first division. This results in 2 genetically identical embryos because they were formed from the same fertilized egg.

fraternal twins happen when superset sperms enter separate eggs but they fertilize together. Identical happen when the fertilized egg divided in two while it is still a tiny collection of cells. The sled contained halves then develop into two babies with the same genetic information.

Explanation: