The pollen tube enters the embryo sac through:

In pollen grains released at the $2$-celled stage,where are the male gametes formed?

When the pollen tube enters the embryo sac,it enters through the ..... cells.

Which of the following is a useful method to store pollen grains?

Pollen grains of some plants germinate on the stigma soon,but they burst in water or a dilute sugar solution. Why?

$A$: Initial growth of the pollen tube takes place at the expense of food present in the stigma and style.
$R$: The pollen tube travels intracellularly and chemotactically.