Identify the correct modes of entry of the pollen tube in the diagrams given below.

How many of the following plants have a single ovule in their ovary?
Wheat,Papaya,Orchid,Paddy,Mango

Name the parts of an angiosperm flower in which development of male and female gametophyte take place.

Select the option that represents the correct sequence of events in the process of fertilization in flowering plants:
$(I)$ Movement of male gametes towards the egg cell and central cell
$(II)$ Formation of pollen tube
$(III)$ Dehiscence of anther
$(IV)$ Germination of pollen grain
$(V)$ Fusion of nuclei (Syngamy and Triple Fusion)
$(VI)$ Entry of male gametes into the synergid
$(VII)$ Deposition of compatible pollen on the stigma

Match the following columns:

Column-$I$ (Organisms)	Column-$II$ (Chromosome number in meiocytes)
$P$. Housefly	$I$. $38$
$Q$. Rat	$II$. $42$
$R$. Dog	$III$. $12$
$S$. Cat	$IV$. $78$
$T$. Fruit fly	$V$. $8$

Non-viable seeds are produced by