When the pollen tube enters the ovule through the integuments,the process is called:

What does the filiform apparatus do at the entrance into the ovule?

Growth of pollen tube towards the embryo sac is:

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.

Mention the viability of pollen grains.

When the pollen tube enters the ovule through the funiculus or the integuments,it is called: