its formation by fusion of secondary nucleus with several sperms
Solution
In some seeds like black pepper and beet, remnants of nucellus are also persistent this persistent nucellus is called perisperm. The cells of endosperm tissue are filled with reserve food materials and are used for the nutrition of the developing embryo. The main difference is perisperm is present in seeds and endosperm is present in developing embryo as its reserved food which is completely consumed by is during development.