Monosporic Female Gametophyte Development — NEET Biology

Which of the following statements are correct? S1: The tapetum is the innermost layer of the microsporangial wall, composed of cells with dense cytoplasm and often multiple nuclei, which nourish developing pollen grains. S2: The exine of pollen grains is a thin, continuous layer made of cellulose and pectin, and is resistant to degradation by most enzymes. S3: Microsporogenesis results in the formation of four functional microspores from a single microspore mother cell through mitotic divisions. S4: The development of the female gametophyte in angiosperms is predominantly monosporic, involving three successive free nuclear mitotic divisions of the functional megaspore. S5: In a mature embryo sac, the egg apparatus is located at the chalazal end and consists of one egg cell and two synergids. S6: The filiform apparatus, located in the antipodal cells, plays an important role in guiding pollen tubes into the embryo sac.