In the embryo sac,after which stage does cell wall formation occur?

Identify the correct option for $P$ and $Q$ based on the number of ovules in an ovary:
$P$: Number of ovules in an ovary is one
$Q$: Number of ovules in an ovary is more than one
$\quad\quad\quad\quad P \quad\quad\quad\quad\quad\quad\quad\quad Q$
$(A)$ Papaya,Watermelon,Mango | Wheat,Paddy,Orchid
$(B)$ Wheat,Paddy,Orchid | Papaya,Watermelon,Mango
$(C)$ Wheat,Paddy,Mango | Papaya,Watermelon,Orchid
$(D)$ Papaya,Watermelon,Orchid | Wheat,Paddy,Mango

Identify the labelled parts $X, Y$ and $Z$ from the given figure of an embryo sac:

An ovule in which the funiculus lies close to the micropyle is known as:

The megasporangium is equivalent to which structure in angiosperms?

Which of the following is true for a typical mature embryo sac?