Identify structures A, B, C and phenomena P1, P2, P3.

Out of two, one male gamete moves towards the egg cell and fertilize the egg cell to form a diploid zygote. This fusion is known as syngamy. The second male gamete move towards secondary nucleus & get fused with diploid secondary nucleus (formed by fusion of two polar nuclei). This fusion is known as triple fusion or vegetative fertilization resulting formation of a triploid (3n) structure. It is called primary endosperm nucleus (PEN). Since two types of fusions, syngamy and triple fusion take place in an embryo sac, the phenomenon is termed double fertilization.