The plant parts which consist of two generations one within the other: (a) Pollen grains inside the anther (b) Germinated pollen grain with two male gametes (c) Seed inside the fruit (d) Embryo sac inside the ovule

Step-by-step solution

A typical anther is bilobed. The two anther lobes are separated by a deep groove in front and are attached by a band of sterile vasculature tissue called connective. Each anther is a four sided tetragonal structure consisting of four microsporangia located at corners, two in each lobe. Hence, a mature anther is tetrasporangiate. Microsporangia form pollen sacs which on maturity become filled with pollen grains. Embryo sac: It is also called as the female gametophyte and is located in the nucellus. An ovule generall