Name the part of the gynoecium that determines the compatible nature of the pollen grain.

In . . . . . . pollen grains cause allergy.

Identify the correct sequence of events of pollen-pistil interaction given below.
$(a)$ Pollen tube grows through the stigma,style and reaches the ovule.
$(b)$ Pollen grain lands on the stigma.
$(c)$ Pollen germinates to form pollen tube.
$(d)$ Pollen tube carrying $2$ male gametes enters the ovule.
Choose the correct option.

$A$: 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 which cell's cytoplasm are both male gametes first released?

In the diagram given below,show the path of a pollen tube from the pollen on the stigma into the embryo sac. Name the components of the egg apparatus.