Fertilization is depicted by the condition:

Fusion of egg and male gamete $- P$
Fusion of secondary nuclei and male gamete $- Q$
Select the correct option for $P$ and $Q$.
$\quad\quad P \quad\quad\quad Q$

Assertion: Double fertilization is a characteristic feature of angiosperms.
Reason: Double fertilization involves two fusions.

Double fertilization was first discovered by Nawaschin $(1898)$ in

Select the incorrect statement.

What is meant by double fertilization? Explain.