The formation of embryo sac is called

Identify the parts of the pistil labeled as $P$,$Q$,and $R$:
Receptive surface for pollen grains $- P$
Elongated slender part of the pistil $- Q$
Basal swollen part of the pistil $- R$
$\quad\quad\quad\quad P \quad\quad\quad Q \quad\quad\quad R$

Identify the location and function of the following structures in an angiosperm ovule:
$1.$ Nucellus
$2.$ Filiform apparatus

The nutritive tissue present in the ovule is called

What is the ploidy of the megaspore mother cell $(MMC)$?

Functional megaspore in an angiosperm develops into an