Fertilization

In human females, meiosis-II is not completed until?

1.	Puberty	2.	Fertilization
3.	Uterine implantation	4.	Birth

Receptors for sperm binding in mammals are present on:

1.	Perivitelline space	2.	Zona pellucida
3.	Corona Radiata	4.	Vitelline membrane

Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true?

1.	The were conceived through in vitro fertilization.
2.	They have 75% identical genetic content.
3.	They are monozygotic twins.
4.	They are fraternal twins.