Members of the Nostoc Genus Have Large Numbers of Thylakoid

Multiple Choice

Members of the Nostoc genus have large numbers of thylakoid membranes,and many have gas vesicles.What statement is also most likely true about Nostoc?

A) They are pathogenic.
B) They form an endosymbiotic mutualism with plant roots.
C) They are photoautotrophs.
D) They are methanogens.
E) They are archaea.