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

Which of the following in the female gametophyte of an angiosperm helps in guiding the pollen tube for fertilizing the egg?

What is the function and location of the filiform apparatus in synergids?

By which process does the tip of the pollen tube rupture within the embryo sac?

$A$: 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.

In angiosperms,the pollen tube releases its male gametes into the .......