Which one of the following statements with regard to embryonic development in humans is correct?
Cleavage divisions bring about considerable increase in the mass of protoplasm
In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second
With more cleavage divisions, the resultant blastomeres become larger and larger
Cleavage division results in a hollow ball of cells called morula
Which of the following secretes the hormone relaxin during the later phase of pregnancy?
Identify $X$ from figure :
The role of placenta is
$A$ : If fertilization occurs, the corpus luteum is rescued from regression by human chorionic gonadotropin, which is produced by placenta.
$R$ : In first trimester the corpus luteum stimulates by $hCG$ is responsible for the production of progesterone.
During the course of development, cells in various regions of embryo become variable in morphology and eventually perform diverse functions. This process is known as