The free-living,nitrogen-fixing cyanobacterium which also forms a symbiotic association with the water fern $Azolla$ is.......

Which photosynthetic pigments are present in algae?

What is the dominant phase in the alternation of generations in algae?

In $Ulothrix$,sexual reproduction is by

Which of the following groups secrete and deposit calcium carbonate and appear like corals?

$A$ : Sexual reproduction shows considerable variation in the type and formation of sex cells in members of $Chlorophyceae$.
$R$ : It may be isogamous,anisogamous and oogamous.