AP BIOLOGY

Detailed explanation-1: -vascular plants produce cells called spore mother cells-since they will give rise to spores-in spore cases (sporangia). Spore mother cells are usually surrounded, during development, by a special nutritive tissue. In the more primitive groups, each sporangium holds many mother cells.

Detailed explanation-2: -In moss sporophyte plant, spores are produced in a capsular structure known as sporangium. The sporangium is attached to the gametophyte and obtains its nutrition with the help of a small stalk known as seta (Figure 2). The male gametes in these plants swim through the water to reach the female gamete.

Detailed explanation-3: -In the sporophyte phase a diploid (having two sets of chromosomes) plant body grows and eventually produces spores through meiosis. These spores divide mitotically to produce haploid (having a single set of chromosomes) gamete-producing bodies called gametophytes.

Detailed explanation-4: -Diploid sporophyte cells undergo meiosis to produce haploid spores. Each spore goes through mitotic divisions to yield a multicellular, haploid gametophyte. Mitotic divisions within the gametophyte are required to produce the gametes. The diploid sporophyte results from the fusion of two gametes.