Q. why there are about 100-200 billions galaxies
and about so human beings !?

Ans. Perhaps GOD wants
to give one galaxy to each one of us
and allow us to do whatsoever
(including all kind of worlds
and creatures and also a kind of HEREAFTER)
and then compares the our worlds.
HE shall show us !! that
the best one is
the one HE HIMSELF has created
and the rest are
... !!! ( ??? )