A boy who has not passed through puberty sustains an injury to his anterior pituitary such that $FSH$ is no longer released, but $LH$ secretion is normal. After he grows to maturity, one would expect that he would
Develop secondary sex characters
Be sterile
Have improper functioning of the testicular interstitial cells
Both $(a)$ and $(b)$
Blood flowing in umbilical cord of mammalian embryo is
Tertiary egg membranes are lacking in mammals with the exception of the
$A$ : The most immediate effect of $FSH$ is the maturation of existing late primary or secondary follicle.
$R$ : $A$ rising level of $FSH$ causes the developing egg within the follicle to complete the first meiotic division to form a secondary oocyte.
After gastrulation the roof of archenteron is formed by
Embryologists can presume the future organs of the embryo in