Answer:
Rhizopus & Spirogyra species are isogamous filamentous green algae and appear as an elongated thread and filament composed of cylindrical shells .Spirogyra belongs to Chlorophyta class having plastic pigment with a starch gain characteristics.
Explanation:
Spirogyra , a fresh water filamentous alga , also exhibits conjugation , where two nearby filaments develop extensions that contact each other . The black bread mold, Rhizopus reproduces asexually by spores and sexually by conjugation . During conjugation , the tips of short hyphae act as gametes and fuse.