Question

Which of the following describes a difference between how monozygotic and dizygotic twins develop?

a) Monozygotic twins share the same placenta, while dizygotic twins have separate placentas.
b) Monozygotic twins are always of different sexes, while dizygotic twins are always of the same sex.
c) Monozygotic twins have different genetic makeup, while dizygotic twins have identical genetic makeup.
d) Monozygotic twins develop from two different eggs, while dizygotic twins develop from a single fertilized egg.

Answer 1

The correct answer is:
a) Monozygotic twins share the same placenta, while dizygotic twins have separate placentas.

Monozygotic twins, also known as identical twins, develop from a single fertilized egg that splits into two embryos. As a result, they share the same placenta. On the other hand, dizygotic twins, also known as fraternal twins, develop from two separate eggs fertilized by two different sperm cells. Each of these embryos has its own placenta.

Answer 2

d) Monozygotic twins develop from two different eggs, while dizygotic twins develop from a single fertilized egg.

Step-by-step explanation:

The main difference between monozygotic (identical) twins and dizygotic (fraternal) twins is that monozygotic twins develop from a single fertilized egg that splits into two embryos, while dizygotic twins develop from two separate eggs that are fertilized by different sperm.

Thus, the correct answer is d) Monozygotic twins develop from two different eggs, while dizygotic twins develop from a single fertilized egg.