Foetus is nourished by

Stem cell can give rise to/the

The persistence of corpus luteum during pregnancy is due to a hormone known as

The hormone released from 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.

The role of placenta is