Which one of the following is the most likely reason for the regular menstruation cycle not occurring in females?

1.	Fertilisation of the ovum
2.	Maintenance of the hypertrophical endometrial lining
3.	Maintenance of a high concentration of sex hormones in the bloodstream
4.	Retention of well-developed corpus luteum

Seminal plasma in humans is rich in:
1. fructose, calcium and certain enzymes
2. fructose and calcium but has no enzymes
3. glucose and certain enzymes but has no calcium
4. fructose and certain enzymes but is poor in calcium

The correct sequence of spermatogenetic stages leading to the formation of sperms in a mature human testis is
1. spermatocyte$\to$ spermatogonia$\to$ spermatid $\to$sperms
2. spermatogonia$\to$ spermatocyte $\to$spermatid $\to$sperms
3. spermatid $\to$spermatocyte $\to$spermatogonia$\to$ sperms
4. spermatogonia$\to$ spermatid $\to$spermatocyte $\to$sperms

In humans, at the end of the first meiotic division, the male germ cells differentiate into
1. primary spermatocytes
2. secondary spermatocytes
3. spermatids
4. spermatogonia

Which extra embryonic membrane in humans prevents desiccation of the embryo inside the uterus?
1. Chorion
2. Allantois
3. Yolk sac
4. Amnion

Which one of the following statement is incorrect about menstruation?

Which part of the ovary in mammals acts as an endocrine gland after ovulation?

In the human female, menstruation can be deferred by the administration of:
1. LH only
2. Combination of FSH and LH
3. Combination of estrogen and progesterone
4. FSH only

Withdrawal of which of the following hormones is the immediate cause of menstruation?