Question

Researchers have found that about ________ of identical twins share the same placenta and amniotic sac in the womb, and contrary to expectations, this makes them less similar in a number of ways as they grow up.

a) 10%

b) 25%

c) 50%

d) 75%

Answer 1

Approximately 75% of identical twins share the same placenta and amniotic sac, which arises from the zygote dividing at the blastocyst stage and can influence their development and similarities.

Step-by-step explanation:

The question revolves around the development of identical twins and whether they share the same placenta and amniotic sac. Researchers have found that about 75% of identical twins share the same placenta and amniotic sac in the womb. Identical twins arise from the division of a single zygote, which can split at different stages of development. Most commonly, the split occurs at the early blastocyst stage, leading to twins that share a placentas as well as a chorionic cavity. This biological phenomenon contributes to their genetic similarities but can result in various developmental differences as they grow.