Identify the organ system in humans that is derived from all the three embryonic germ layers:
1. cardiovascular system.
2. digestive system.
3. endocrine system.
4. muscular system.

Lactation after child birth is possible due to decrease in the secretion of:
1. HCG
2. oxytocin
3. FSH and LH
4. estrogen and progesterone

The initial phase of the cortical reaction leads to:
1. slow block to polyspermy
2. fast block to polyspermy
3. formation of pronuclei
4. completion of acrosome reaction

Identify the incorrect statement:
1. Spermatogenesis begins at puberty.
2. Secondary spermatocyte has 23 chromosomes.
3. Oogenesis lasts only from puberty until menopause
4. oogenesis begins in fetal life

Identify the incorrect statement:
1. Granulosa cells produce estrogen
2. LH surge is due to peak secretion of progesterone
3. The corpus luteum secretes both progesterone and estrogen along with inhibin
4. FSH acts directly on granulosa cells

The testes of a pre-pubertal boy will have:
1. spermatocytes
2. spermatozoa
3. spermatogonia
4. spermatid

The dilated end of vas deferens are called:
1. corpus
2. seminal vesicle
3. ampulla
4. tubuli recti

Human embryos will develop into female by default due to:
1. presence of an X chromosome
2. an ovarian determining factor
3. presence of a Y chromosome
4. lacks of Y sex chromosome

Labor can be hastened by:
1. progesterone
2. estradiol
3. prostaglandins
4. HCG

A big advantage of the evolution of internal fertilization is:
1. need for large number of gametes to be produced
2. fetuses to be kept warm, moist, nourished, and protected inside the mother
3. synchronous release of gametes by both sexes
4. prevention of dehydration of gametes