Answer :

Fertilization is the fusion of the male gamete (androecium)  & female gamete (gynoecium) which results in the formation of a zygote .
In flowering plants, after the fusion of the sperm nuclei with egg nucleus (in the ovary) fertilization takes place.
The fate of the floral parts are decided after the process of fertilization.
The ovules becomes the seeds.
Hence, seed is considered as a fertilized ovule in Angiosperms(flowering plants). 
Siri66
Flowering plants are also called as angiosperms.In flowering plants almost the reproduction process takes place only with the seeds in which ovules become seeds after fertilization.So the seeds are considered as fertilized ovule in angiosperms.