Answer:
An ovary in an angiosperm flower contains one ovule, in which the cells divide to produce an egg and two polar nuclei. These egg and polar nuclei are haploid. The pollen grain introduces sperm cells which are also haploid. The two haploid sperm cells are introduced into the pollen tube and finally reaches to the ovules. The first sperm cell fuses with the egg and zygote form is diploid in ploidy. The second sperm cell will fuse with the two polar nuclei, and a endosperm form is triploid in ploidy.