D-Only (i)
Correct Answer:- Option-C

Questions: ofthe following statements about primitive streak are true except
‘Ache first sign of gastrulation is the appearance of primitive streak
B:-Primitive streak actively forms mesoderm until the end of fourth week
Primitive streak results from proliferation and movement of cells of epiblast to the median plane of embryonic dise
D:-Primitive streak disappears by the end of fourth week of embryonic life
Correct Answer:- Option ®

Question9::Which of the following statement is/are correct about somites 7

i. Somites give rise to the adjacent epidermis of skin

ii, Formation of somites involves the expression of Hox genes

il, By the end of fifth week, 42 to 44 pairs of somites are present
iv. Crariocaudal segmental pattern of the somites is regulated by the Delta-Notch signaling system

+77
B:All of the above (iii and iv)
பிராடு Gi and i)

D-Only 6, ॥ and i)

Correct Answer:- Option-é
Question10::Which of the following is not a neural crest derivative ?
‘Ac Melanocytes in skin
B:-Cells of anterior pituitary
C-Odontoblasts
D:-Satellte cells
Correct Answer:- Option ®
Question11:-Select the incorrect statement regarding twinning
‘A-Approximately two thirds of twins are dizygotic
Bs-Incidence of monozygotic twinning is approximately the same in all populations
C=Dizygotic twins always have two amnions and two chorions
D-Twin transfusion syndrome occurs in as many as 50% of monochorionic-diamniatic monazygous twins
Correct Answer:- Option-D
Question12:-Which of the following statements is not true about allantois ?
‘Acllantois appears as a diverticulum from the caudal wall ofthe umbilical vesicle
8:15 1೦೦ರ vessels persist as the umbilical vein and arteries
C:Extraembryonic part of the allantois degenerates during the fourth month
D-Blood formation occurs in the wall of allantois during the third to fifth weeks of embryonic life
Correct Answer:- Option-C
Question13:-The protein hormones synthesised by the placenta are all except
Aches
B: Progesterone
C-Human chorionic thyrotropin
D-Human placental lactogen
Correct Answer:- Option ®
Question14:-Which of the following paranmeters in triple test indicate the probability of Down syndrome ?
0 alphafetoprotein
Bs-Increase in unconjugated estriol
Increase in human chorionic gonadotropin
D-Increase in inhibin A
Correct Answer:- Option-C
Question15::Which of the following diseases is transmitted by autosomal recessive mode ?
‘Ac Phenylketonuria
B:-Red green color blindness

C-G6PD deficiency