Define the term 'double fertilization in plants'. After fertilization,name the part in each case which develops into $(i)$ the fruit,(ii) the seeds.

(N/A) Double fertilization: It occurs when one male gamete fuses with the egg cell to form a $zygote$ and the other male gamete fuses with two polar nuclei to form the primary endosperm nucleus (triple fusion).
Since these two processes occur simultaneously in the embryo sac,it is known as double fertilization.
After fertilization:
$(i)$ The ovary develops into the fruit.
(ii) The ovules develop into the seeds.