Answers

Sushant
Aug 2, 2020

In fertilisation (in angiosperm), two types of fusion occur, i.e. syngamy and triple fusion, in the embryo sac. That is why it is called double fertilisation.
Ploidy of cells involved in double fertilisation: Zygote is diploid (2n). It is formed as a result of syngamy, i.e. fusion of two haploid gametes (male gamete + egg). Primary  endosperm nucleus (3n) is formed as a result of triple fusion, i.e. fusion of two haploid polar nuclei with male gamete