Which of the following pigments is present in cyanobacteria?

$......$ bacteria oxidise various inorganic substances such as nitrites,ammonia and use the released energy for $\text{ATP}$ production $:-$

The sex factor in bacteria is:

Cyanobacteria are also referred to as .......

$Thermococcus$,$Methanococcus$,and $Methanobacterium$ are examples of:

Which of the following are symbiotic prokaryotic organisms that fix atmospheric nitrogen?