Auxospores and hormogonia are formed, respectively, by (a) some diatoms and several cyanobacteria (b) some cyanobacteria and many diatoms (c) several cyanobacteria and several diatoms (d) several diatoms and a few cyanobacteria.
Option D Until 1907, auxospore formation was regarded as asexual process but now it is considered as an act of sexual process. The auxospores may be autogamous, isogamous, anisogamous or oogamous. Their pattern of formation differs in pennate and centric diatoms. Formation of hormogonia is the common method of reproduction in Nostoc which are produced by accidental breaking of trichome into several pieces. It may also be formed by death and decay of ordinary intercalary cells. Soon, the hormogonium escapes from mucilage and grows into a new filament and then into a new colony.
