Practice question

Seed plant gametophytes highly reduced matrotrophic depending completely on sporophyte for nutrition and protection throughout life, no independent photosynthesis. Male gametophyte three-celled pollen grain lacks chlorophyll tube cell generative cell plus two sperm, female gametophyte gymnosperms massive haploid within ovule containing archegonia eggs, angiosperm seven-celled eight-nucleate embryo sac within nucellus integuments, both enclosed maternal sporophytic tissues. No free-living photosynthetic phase persists unlike bryophytes where sporophyte dependent on gametophyte or ferns both independent free-living. Dependency ensures sheltered fertilization via pollen tube siphonogamy delivering sperm without external water film, crucial adaptation for terrestrial colonization and dominance.