Final answer:
Identical twins are formed from a single fertilized egg, while fraternal twins are formed from two separate eggs.
Step-by-step explanation:
Identical and fraternal twins are two types of multiples that can be formed during fertilization. The main difference between them lies in the number of fertilized eggs and their genetic makeup.
Identical twins, also known as monozygotic twins, are formed when a single fertilized egg splits into two separate embryos. These embryos share the same DNA and are therefore genetically identical. Identical twins are always the same sex and have similar physical features.
On the other hand, fraternal twins, also known as dizygotic twins, are formed when two separate eggs are fertilized by two different sperm. Each embryo has its own genetic makeup, similar to siblings born at different times. Fraternal twins can be of the same or different sexes and may have different physical features.
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