What is correct for parthenium (Carrot grass)?
$(a)$ It came into India as a contaminant with imported wheat
$(b)$ It causes allergy
$(c)$ Asexual reproduction occurs in its flower
$b$ -correct
$b, c$ -correct
$a$ - correct
$a, b$ - correct
Which one of the following is resistant to enzyme action?
The pollen grain is
In flowering plants meiosis occurs at the time of
The tapetal nuclei in anthers of many angiosperm flowers are
Pollen grains can be stored for several years in liquid nitrogen having a temperature of