What do '$f$' and '$g$' represent in the given figure?

Which whorl of the flower is responsible for producing the female gamete?

The three cells present at the chalazal end form $.....P......$,and the three cells present at the micropylar end form $.....Q.....$.
$\quad\quad\quad \quad \text { P } \quad\quad\quad \text { Q }$

The number of nuclei migrating from each of the micropylar quartet and chalazal quartet to the centre of the normal embryo sac is

Filiform apparatus is found in which part of angiosperms?

Synergids of the $Polygonum$ type embryo sac are