Mammalian placenta is
a cord between mother and foetus
place of attachment in uterus wall where exchange of material between mother and foetus takes place
outer covering of foetus
allantoic part of the uterus
Correct Answer :
B. place of attachment in uterus wall where exchange of material between mother and foetus takes place
Related Questions
Grey cresent is present in
zygote of frog
brain of rabbit
eye of frog
retina of cockroach
Sexual reproduction in larval condition is known as
paedogamy
autogamy
isogamy
anisogamy
When the eggs are released from the ovary of frogs they are at the
primary oocyte stage
secondary oocyte stage
ootid stage
matured ova stage
During fertilization the spermatozoa penetrate through the egg membranes with the help of
flagellum
acrosome
sperm lysins released from the acrosome
mitochondira located at the middle piece
Laternal line system of sense organs present in the skin of tadpole larva
completely disappears during metamorphosis
partialy retained during metamorphosis
partially disappears during later stages of metamorphosis
fully retained in the adult frog
The substance fertilizin is secreted by
ova
sperm
both and
primary spermatogonia
For fertilization of the frog's egg
sperms of same species are essential
sperms do not need penetration
sperms of any animal can fertilize
only presence of male is sufficient
The formation of the neural tube is known as
neurulation
tubulation
crania tion
none of these
Constructive change in the development of frog from tadpole is
disappearance of tail
food habit becoming carnivore
land habit
excretion beocmes mesonephric
Which of the following develops from ectoderm ?
Spinal cord and brain
Liver and heart
Eye and skin
Notochord and vertebral colum.
The expulsion of completely developed foetus from the uterus is known as
ovuation
placentation
gestation
parturition
Oogonia entering the growth phase of oogenesis is called
primary oocyte
secodnary oocyte
ootid
gonocyte
During normal development the activation of the egg is achieved by
vitellogenesis
oogenesis
spermatogenesis
fertilization
Blastopore in frogs development occurs in
blastula and opens in blastocoel
blastula and opens in archenteron
gastrula and opens in blastocoel
gastrula and opens in archenteron
In the human female, the primary oocytes remain small without any growth for
4-5 years
6-8 years
8 - 10 years
12 -14 years
The nervous system, epidermis and hairs and nails are derivatives of
endoderm
mesoderm
ectoderm
chordomesoderm
The formation, development and matura- j tion of the female gamete is called
ovulation
oogenesis
vitellogenesis
folliculogenesis
Which one has the capacity to reproduce without fertilization of eggs ?
Spider
Crow
Honeybee
Earthworm
In frog's egg the divisoin is
holoblastic
meroblastic
diploblastic
triploblastic
A true coelom is covered by
ectoderm
endoderm
mesoderm
ecto and mesoderm
Which of the following does not show metamorphosis ?
Frog
Housefly
Hydra
Mosquito
Metamorphosis is a characteristic feature of
direct ontogenic development
indirect ontogenic development
chordates
embryogenesis in mammals
During metamorphosis, the disappearance of larval organs is called
histogenesis
paedogenesis
histolysis
paedomorphosis
Embryo sac in a hen's egg is formed by
ectoderm
meso derm
somatic mesoderm and endoderm
splanchnic mesoderm and ectoderm
The process of synthesis of yolk by the oocyte is termed
folliculogenesis
oogenesis
vitellogenesis
spermiogenesis
Which of the following do not show parental care over their young ones ?
mammals
lizards
fowls
earwigs
During cleavage, the embryo
enlarges in size
decreases in size
retains the same size at the beginning
gradually enlarges in size
During the development of frog, the ar-chenteron is formed in
early blastula
late blastula
early gastrula
lategastrula
How many cleavages are completed in 16 cell stages of frog's egg ?
3
8
4
12
The allantoic vesicle arises from
foregut
midgut
hindgut
somatopleure