Fraternal twins are produced when

Q. Fraternal twins are produced when

1. single ovum is fertilized by two sperms
2. single fertilized ovum divides into two
3. two ova are fertilized simultaneously
4. none of the above

Answer: Two ova are fertilized simultaneously.

Fraternal twins are produced when two ova are fertilized simultaneously.

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Twins are two people that shared the uterus during a single pregnancy, and one is normally born quickly after the first.
There are two types of twins – identical (monozygotic) and fraternal (dizygotic).

Fraternal twins are also known as "non-identical twins" or dizygotic twins. They happen when two ova are released from the ovary at the same time, and each is fertilized by a different sperm. This results in the birth of fraternal twins. They can be of different sexes. Genetically, they are no more similar than any two siblings.

Identical twins or monozygotic twins: A single ovum is fertilized to form one zygote. This zygote later splits, and each half of the zygote becomes a twin. The twins have the same genes.

To form identical twins, one fertilised egg (ovum) splits and develops two babies with exactly the same genetic information. This differs from fraternal twins, where two eggs (ova) are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times.

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Fraternal twins in humans are produced when

1. Two sperms fertilize an ovum and the first two blastomeres separate from each other
2. One sperm fertilizes an ovum and the first two blastomeres separate from each other
3. Egg develop parthenogenetically and first two blastomeres separate from each other
4. Two ova are fertilized simultaneously

Answer: Fraternal twins in humans are produced when two ova are fertilized simultaneously.

Identical twins will be produced, when

1. One spermatozoan fertilizes two ova.
2. One ovum is fertilized by two spermatozoa.
3. Two eggs are fertilized.
4. One fertilized egg divides into two blastomeres and they become separate.

Answer: Identical twins will be produced, when one fertilized egg divides into two blastomeres and they become separate.

A blastomere is a type of cell produced by cleavage (cell division) of the zygote after fertilization and is an essential part of blastula formation.