Two spines in $Trapa$ fruit ($Singhara$ fruit) are modifications of

What is the size of $Wolffia$ $globosa$?

In a flower, if a whorl member of the perianth or corolla overlaps without any particular direction, then the aestivation is known as:

Match the following columns regarding placentation in plants:

Column-$I$ (Placentation)	Column-$II$ (Examples)
$P$. Parietal	$I$. Dianthus,Primrose
$Q$. Axile	$II$. Sunflower,Marigold
$R$. Marginal	$III$. Pea
$S$. Free central	$IV$. Lemon,China rose,Tomato
$T$. Basal	$V$. Mustard,Argemone

Mark the incorrect statement.

In . . . . . . placentation,the placenta forms a ridge along the ventral suture of the ovary.