Correct Answer - C
(c) In Ulothrix/Spirogyra, meiosis takes place at the time of zygospore germination. It takes place when (+) and (-) plants/filaments results in the formation of diploid zygote (2x). Zygote is tetraflagellated, it secretes a thick wall and becomes non-motile to form diploid zygospore. Under favourable conditions, zygospore undergoes zygotic meiosis to form motile tetraflagellated zoomeiospores or non-motile aplanomeiospores. Each meiospore (haploid) germinates to new filament of (+) (-) strain.
