The pollen tube usually enters the embryo sac

Step-by-step solution

After entering the wall of the embryo sac the pollen tube during its entry into the embryo sac passes through the nucellar cells and the synergids, e.g. Fagopyrum. The pollen tubes passes between the egg and one synergid. In Cardiospermum, it passes between embryo sac wall and synergid. In Oxalis, it passes directly through a synergid. In Viola, it enters a synergid and makes its way through the base of the synergid. In normal cases only one synergid destroys by the impact of the pollen tube and the other remains i