CBSE Class 10 Answered

Pollen grains reach the ovary through a pollen tube. The pollen tube grows and enters the ovule where it bursts at the tip releasing the male gametes. One of the male gamete fuses with the egg, the female gamete. The fusion of the male gamete with the female gamete is called fertilization. This results in the formation of a diploid zygote. The zygote develops into the embryo. The other male gamete fuses with the polar nuclei. This results in the formation of a triploid nucleus called the endosperm nucleus. Since the process of fertilization involves two fusions, it is called double fertilization.