Twins that result from two separate fertilized ova are called?

Twins that result from two separate fertilized ova are called?

• A. Monozygotic
• B. Dizygotic
• C. Conjoined
• D. Heterozygous

Answer: (B)

Twins that come from two separate fertilized ova are dizygotic (fraternal) twins. This happens when two eggs are released and fertilized by two different sperm, producing two genetically distinct zygotes that develop into two individuals. Because they arise from separate eggs and sperm, these twins are not genetically identical and can be the same or different sex. They typically have separate placentas and amniotic sacs. This fits the description because it explicitly involves two zygotes from two ova. In contrast, monozygotic twins come from one zygote that splits, often sharing a placenta and/or amniotic sac; conjoined twins are a variant of monozygotic twinning where division is incomplete. Heterozygous is a genetic term describing alleles rather than the mechanism of twinning.

Twins that come from two separate fertilized ova are dizygotic (fraternal) twins. This happens when two eggs are released and fertilized by two different sperm, producing two genetically distinct zygotes that develop into two individuals. Because they arise from separate eggs and sperm, these twins are not genetically identical and can be the same or different sex. They typically have separate placentas and amniotic sacs.

This fits the description because it explicitly involves two zygotes from two ova. In contrast, monozygotic twins come from one zygote that splits, often sharing a placenta and/or amniotic sac; conjoined twins are a variant of monozygotic twinning where division is incomplete. Heterozygous is a genetic term describing alleles rather than the mechanism of twinning.