After culturing the anther of a plant,a few diploid plants were found along with haploid plants. The diploid plants could have arisen from

The chromosomal number in a cell of a flowering plant is:

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Zygote	$(1)$ Endosperm
$(b)$ $PEN$	$(2)$ Embryo
$(c)$ Ovule	$(3)$ Fruit
$(d)$ Ovary	$(4)$ Seed

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	$V$. $8$

Rose plants produce large,attractive bisexual flowers but they seldom produce fruits. On the other hand,a tomato plant produces plenty of fruits though they have small flowers. Analyze the reasons for the failure of fruit formation in rose.

Pollen grains of many species cause severe allergies and bronchial afflictions in some people,often leading to chronic respiratory disorders such as .....