According to Bradley and Carr,the nitrogen fixation takes place in

The cell of a mycoplasma contains:

Cells of $Nostoc$ are

The given figure shows the structure of filamentous blue-green algae,Nostoc,with a structure marked as $X$. Select the option which shows the correct identification of $X$ with its feature.

Which bacteria are responsible for the digestion of cellulose in the food of ruminant animals?

Which of the following is a bacterial domain?