Answer:
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.
Two risks of drugs are health decline, and mental illness.
