Question

Identical twins can result from:

a) This stage in meiosis - sister chromatids move as two newly individual chromosomes.
b) Genetic mutation in one zygote.
c) Fusion of two separate sperm with two separate eggs.
d) Fusion of one sperm with two separate eggs.

Answer 1

Identical twins can result from the splitting of a zygote into two separate offspring during early development, leading to the birth of monozygotic twins. The timing of the split determines whether the twins will have individual placentas or share a placenta and a chorionic cavity.

Step-by-step explanation:

Identical twins can result from the splitting of a zygote into two separate offspring during early development. This process, known as embryo splitting, leads to the birth of monozygotic (or identical) twins. The zygote can split as early as the two-cell stage or during the blastocyst stage, resulting in different scenarios with regards to placenta sharing.

In the scenario where splitting occurs at the two-cell stage, each twin will have individual placentas. On the other hand, if splitting occurs during the blastocyst stage, the twins will share a placenta and a chorionic cavity.